There are a lot of changes here:
- The main_content FrameLayout is now main_fragment (more logical name).
- TunnelEntry now stores a Context instead of a TunnelEntryLoader (so
  it can be instantiated inside the detail Fragment).
- The activity_navdrawer layout is now an alias to a one-pane or two-pane
  layout depending on screen size.
- Subclasses of I2PActivityBase can now override canUseTwoPanes() to enable
  and use the two-pane layout (for devices that support it).

Broken: cannot find net.i2p.i2ptunnel.I2PTunnel
(but it can when launching the router)

Temporary; will eventually be in an about menu in settings

The navigation drawer has been (mostly) migrated to link to Activities instead
of Fragments. Only Activities can be searched via the inbuild Android search
function, which uses Intents.

This should have enabled the current navigation drawer entry to be highlighted
by the call to setItemChecked() in selectItem(), but it still doesn't work.

Side-effect: some constant strings are now public

- Migrated I2PActivityBase and subclasses to Fragment
- Added new MainActivity with navigation drawer to handle Fragments
- Added MainFragment to navigation drawer

Code compiles, installs and runs. Known bugs created:
- Some buttons now fail (can't use an Intent with a Fragment)
  -> Migrate usage of Intents to Fragment transactions
- New install/upgrade dialogs are commented out
  -> Migrate old Dialogs to DialogFragments

- Update release notes
- Lower log levels
- Spelling fixes on settings page

- Clean up debug text on main screen
- Move most logging from System.err.println to Util
- Stub out HTTP auth handler
- Don't restart Peers page on orientation change
- Add inbound/outbound arrows, not loaded yet
- Tweak log levels

- More updates to release notes

- Toast on cache load
- Don't lose current page on orientation or keyboard hidden events
- Implement reload
- Quit is the new stop

- Switch from URI to Uri in the WV Client
- Canonicalize resource URIs if necessary
- Switch from HashMap to SharedPrefs in CacheProvider
- Use cache when going forward too
- CacheProvider remove old entries in onCreate()
- CacheProvider cleanup
- gc on router stop
- Add reload menu item
- Don't return to welcome page on activity restart
- Notification on client tunnels up/down