new light guy physics !
readjust light guy speed and forces for new physics
readjust arenas and prefabs for new physics
normalize keyboard input when getting a diagonal
Merge branch 'master' of https://github.com/le-poulpe/jaimelesplantesenpot

Conflicts:
	Boucucle/Assets/Art/Them/LightGuy/LightGuy.prefab
	Boucucle/Assets/Scenes/proto_01.unity
	Boucucle/Assets/Scripts/LightGuy.cs