NDT changes adapted from Vuze/BiglyBT, and changes for I2P.

Vuze/Bigly is based on NDT 3.6.2b, so their changes are
manually merged here.
This rev does not compile, requires swingemu package to follow.
Changes:
- Add external start hook to Tcpbw100 from BiglyBT
- Replace all Swing/AWT classes with emulations from BiglyBT
  (included in next checkin)
- Leave classes in edu.internet2.ndt package rather than
  moving to com.vuze.plugins.mlab heirarchy as Vuze/BiglyBT did
- Change IPv6 support setting to use I2P class for detection
- Change in-progress field to an AtomicBoolean
- Change from System to I2P logging
- Change JSON library package
- Comment out some applet code
- Javadoc fixes