TowerSprite : the towerSprite has the color of his associated base.
TowerSprite : change the sprite for the level 0 and the other level.
BaseSprite : fix bug when you can control the IA !
Tower : you can build tower from any of your base, if you have the
associated base.
Merge branch 'master' of https://github.com/cchampet/Java_nanowars.git

Conflicts:
	src/renderer/BaseSprite.java