Covers router, unsigned router, plugin, and news updates

Don't count Jetty RolloverFileOutputStream in the thread group,
to fix restart of a plugin

- Fix bug that left server acceptor thread running after close
- Add destroy() methods to release all resources when closing a tunnel for good,
  particularly the streaming timer threads
- Use COWAL to prevent concurrency problems
- Javadocs
Streaming:
- Don't return null from accept() any more; actually throw
  ConnectException as the javadocs have always specified
- Throw ConnectException from accept() if interrupted; previously caught and ignored
- Throw exceptions from ConnectionHandler.accept(), not higher up
- Close ServerSocket when ConnectionManager is shut down
- Synchronize setActive(), clear queue when starting to accept,
  better handling of calls that don't change state
- Javadocs
ConfigClientsHelper: Call isPluginRunning() less often
PluginStarter: Simplify detection of active threads

Above changes mostly in support of zzzot plugin implementing ClientApp
and being able to shut down completely so there are no threads
in its thread group, so /configclients will all show status as stopped.
Previously, the I2PTunnelServer acceptor thread and
one or more streaming timer threads would remain.

   - Convert to RouterApp and remove update hooks from context
     (ticket #1185)

 - volatile -> atomic
 - unused code and fields
 - closing streams
 - hashCode / equals
 - known non-null
 - Number.valueOf
 - new String
 Still avoiding SAM, BOB, SusiMail

  - Add support for requesting an encrypted reply
* NetDB:
  - Add support for encrypted DatabaseSearchReplyMessage and DatabaseStoreMessage
    in response to a DatabaseLookupMessage
* PRNG: Cleanups using Collections.singletonMap()
* Router utils: New RemovableSingletonSet
* TransientSessionKeyManager:
  - Support variable expiration for inbound tag sets
  - Several efficiency improvements
* VersionComparator: Add static method, use most places

            start delayed clients from SimpleTimer2 instead of Job queue (ticket #670)

   - Notify manager about all available update methods at once, so the priority
     system works and it doesn't only update via HTTP
   - Start router update download at startup if available
   - Only check plugins when core version increases, not decreases, so we
     don't update plugins when downgrading
   - Limit length of URL shown on summary bar

Convert LocaleWebAppHandler from extending WebAppContext to
extending HandlerWrapper, since handle() is now final in WebAppContext.
Untested.

- Remove unused UpdateTypes
- Only try applicable updaters when updating
- Javadoc fixes

implementing out-of-console updaters like i2psnark.

- Add new update interfaces in net.i2p.update
- All update implementations moved to routerconsole update/
- Implement an UpdateManager that registers with the RouterContext
- UpdateManager handles multiple types of things to update
  (router, plugins, news, ...) and methods of updating (HTTP, ...)
- UpdateManager maintains list of installed, downloaded, and available versions of everything
- Define Updaters that can check for a new version and/or download an item
- Individual Updaters register with the UpdateManager obtained from
  I2PAppContext, identifying the type of update item and
  update method they can handle.
- Updaters need only core libs, no router.jar or routerconsole access required.
- All checks and updates are initiated via the UpdateManager.
- All status on checks and updates in-progress or completed are
  obtained from the UpdateManager. No more use of System properties
  to broadcast update state.
- All update and checker tasks are intantiated on demand and threaded;
  no more static references left over.
- Split out the Runners and Checkers from the Handlers and make the inheritance more sane.
- No more permanent NewsFetcher thread; run on the SimpleScheduler queue
  and thread a checker task only to fetch the news.
- No more static NewsFetcher instance in routerconsole.
  All helper methods that are still required are moved to NewsHelper.

The UpdateManager implements the policy for when to check and download.
All requests go through the UpdateManager.

For each update type, there's several parts:
    - The xxxUpdateHandler implements the Updater
    - The xxxUpdateChecker implements the UpdateTask for checking
    - The xxxUpdateRunner implements the UpdateTask for downloading

New and moved classes:

web/				update/
----				-------
new				ConsoleUpdateManager.java

new				PluginUpdateChecker.java from PluginUpdateChecker
PluginUpdateChecker 		-> PluginUpdateHandler.java
PluginUpdateHandler.java	-> PluginUpdateRunner

new				UnsignedUpdateHandler.java
UnsignedUpdateHandler		->  UnsignedUpdateRunner.java
new				UnsignedUpdateChecker from NewsFetcher

UpdateHandler.java remains
new				UpdateHandler.java
new				UpdateRunner.java from UpdateHandler

move				NewsHandler from NewsFetcher
new				NewsFetcher
new				NewsTimerTask

new				DummyHandler


Initial checkin. Unfinished, untested, unpolished.

      to eliminate races with ReadConfigJob

    - Auto-update plugins after a router update
    - Add update-all button

    - Only stop a plugin before update if it was running
    - Don't start a plugin after update if it was disabled
    - Disable plugin if it fails version checks at startup

    - Enforce min and max Jetty versions at plugin installation
    - Enforce I2P, Java, and Jetty versions at plugin startup too

Jetty 6 package.

- Add several jars from the Jetty 6 distribution
- Update jetty.xml
- Add context XML files
- Update WorkingDir to migrate the content XML files
- Update RouterConsoleRunner and LocaleWebAppHandler
- Remove all old Jetty 5.1.15 local mods;
  this will break Seedless using a custom Server() constructor
- Update I2PRequestLog to be a mod of NCSARequestLog from 6.1.26
- Put I2PRequestLog in its own jar
- Copy MultiPartRequest and other required classes from Jetty 5.1.15
  and add it to susimail, as the replacement MultiPartFilter in
  Jetty 6 is difficult to migrate to, and does not support content-type
- Update i2psnark for Jetty 6
- Disable i2psnark RunStandalone, unused and instantiated Jetty 5
- Fix up all webapp build.xml to reference new jars

Not yet working: Plugin/webapp run detection and stopping, eepsite CGI
Not well tested: Plugins, classpaths, webapps

    * DataHelper: Speed up eq() (Ticket #437)
    * HTTPServer: Strip inbound X-Accept-Encoding header
    * netdb.jsp: HTML fixes
    * Plugins: Log error when console server not found
    * Reseed: Log tweak

      The only defecency is that if one is running, that it considers the
      entire pliugin to be running. I'm not sure if that is a good thing
      or a bad thing, but the other code checks threads that way.

    Loading a class would be one of them!
    So we do a quick check first, If it bombs out, we delay and try again.
    If it bombs after that, then we throw the ClassNotFoundException.

      - Set classpath for specific client only, not for the whole JVM
      - Use ConfigDir() not AppDir()