remove all requestUpdate() calls from GodNavigation.

Because the frames are invoked by the game itself, it is not needed to call for extra frames while moving.
change gameloop to frame rate limited loop

* only draws if there is enough time or we are significantly behind
* sleeps if there is time left
turn vsync off by default, use viewer reference in game
Merge pull request #8 from lanice/gameloop_enhancement

Gameloop enhancement
add shader reload feature (F5)
Merge remote-tracking branch 'origin/master' into simple_shading

Conflicts:
	src/game.cpp
	src/game.h
disable configuration of graphics context, as not working for some reason

maybe related to own shader?...
playing around with terrainId + lighting