Big savings is on client side (two less threads per connection)
 - Move client pool from static inI2PTunnelClientBase to TCG.
 - Use client pool for some server threads
 - Run some things inline that were formerly threads
 - Client-side I2PTunnelRunner thread used to do nothing but start 2 more
   threads; now it runs one inline (like we do for server-side HTTP)
 - Javadocs and cleanups
Was originally intended to reduce load for high-traffic servers
but most of the savings for now is on the client side.
Ref: http://zzz.i2p/topics/1741
Todo: Figure out how to run the HTTP client-side gunzipper inline too
Todo: More server-side improvements

---

Client side:

before:
4-5 threads, 1-2 pooled

  I2PTunnel Client Runner (BlockingRunner from client pool)
      starts I2PTunnelRunner or I2PTunnelHTTPClientRunner and exits
          starts StreamForwarder toI2P and waits
          starts StreamForwarder fromI2P and waits
              starts HTTPResponseOutputStream (HTTP gunzip only) (from client pool)
now:
2-3 threads, 1-2 pooled

  I2PTunnel Client Runner (BlockingRunner from client pool)
      runs I2PTunnelRunner or I2PTunnelHTTPClientRunner inline
          starts StreamForwarder toI2P and waits
          runs StreamForwarder fromI2P inline
              starts HTTPResponseOutputStream (HTTP gunzip only) (from client pool)

---

Server side:

before:
1-4 threads, 0-1 pooled

  Server Handler Pool (Handler from server pool) execpt for standard server, blockingHandle() inline in acceptor
      starts I2PTunnelRunner or CompressedRequestor and exits
          starts StreamForwarder toI2P and waits   (inline for HTTP)
          starts StreamForwarder fromI2P and waits  (except not for HTTP GET)

now:
1-4 threads, 0-2 pooled

  Server Handler Pool (Handler from server pool) execpt for standard server, blockingHandle() inline in acceptor
      starts I2PTunnelRunner or CompressedRequestor and exits (using client pool)
          starts StreamForwarder toI2P and waits   (inline for HTTP)
          starts StreamForwarder fromI2P and waits  (except not for HTTP GET)

Fix encoding for filename in Content-Disposition header
New icon from Silk, same license as the others

It was starting both the v3 and v1 acceptors.

- 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.

so peer ordering does not change across restarts

  - Add new opentrackers, remove welterde
  - Support multiple default opentrackers
  - Don't link to opentrackers at the top

Recognize router.newsRefreshFrequency=0 as "never"

was deleted out from under us (ticket #1407)

ECDSA default for all new server tunnels
ECDSA default for streamr client tunnels
Fix display of server destination on edit page when not running (privkey file path wasn't absolute)
Fix display of persistent client key b32 on edit page when not running
Fix display of server sig type on edit page when we have a privkey file
Add KeysAndCert.getSigType()
Javadocs

Fix history.txt UTF-8 breakage
Javadoc fixes after review

Console /debug: Move DHT section to bottom