Correction of bugs : missile's speed and support tower
Solving the areaMissile concurrent modification exception
Optimisation of tower's characteristics
Defined a new enum AttackType for the missiles
Medical tower effect now working
Check if the tower has to be activated according to the unit's PlayerType and the Tower's class
New class Effect to apply modifiers
Frost modifier now working
Prevent from applying twice the same effect to the same unit
Shield modifier now working
Tower can change owner if the corresponding base has been captured
Merge branch 'thomas'

Conflicts:
	src/GameEngine/GameManager.java
	src/GameEngine/WarManager.java
Merge branch 'aurelie'

Conflicts:
	src/GameEngine/GameManager.java
View - Displaying AreaMissile (timer)
Get ready to merge