Pingpong 3.0

* Rewrote backend in Dart
* Removed Tournaments (it was unused)
* Removed points collection, now saved in games
* two game collections: active_game and game
  * active_games are exposed via rest
  * games are only the completed games. Essentially read-only
* Refactored reports to be stored as aggregate values, updated upon game completion
* Redesigned team matchup algorithm to provide better insight.
  * A better matchup is one where the team is more likely to get to deuce
  * A vague numeric score is provided to rank the matchups
* Refactored much of the front end to be leaner and use less globals
* Added Tests
Fix: Undo event leaks after a gameover
Fix server to accept connection on any interface

instead of being restricted to localhost only
Revert "Update dart code to build under dart 1.5"

This reverts commit 776d9481e26821c19cf2f7ce07e14dda1f9e143c.
Merge remote-tracking branch 'upstream/master'