Fix exceptions when sending `end` frame.
Merge branch 'client' into server

Conflicts:
	server/game_engine.py
Fix multiple sending of `end` frame.
Fix bug with `end` frame.
Merge branch 'client' into server
Merge branch 'server' of github.com:tdubourg/spylight into server
Minority change.
Minority fix.
Fix server shutdown process.
Minority change.
Fixed various problem with the turn and shoot events. The walk speed is now sent as a float instead of string. Added the step durations in game_constants. the server should use these ones instead of the ones from the cfg file
Merge branch 'client' of github.com:tdubourg/spylight into client
Merge branch 'server' into client
fixed another bug with the turn event, fixed the end game handling. It should not crash anymore