Add: Thread safe linked list in InGame

The linked list implementation was causing conncurrent
modification errors. Introduced ConcurrentLinkedQueue
to make the list thread safe. Changed the for loops
to foreach loops.
Fix: Multithreading on overlaymenu

Added synchronization blocks to ColorSquare.java
Merge branch 'Threading' into Ingame
Merge: Threading into InGame
Change: Target cross colors and transparency
Fix: Bullets passing target
Fix: tried to fix random crashing
Fix: Missile building collision not damaging building

Missiles that exploded on impact with building would not destroy
building
Added the explosions to ExplosionTracker to resolve the issue.
Add: Better building explosion effects

Buildings now take 5 hits before collapsing.
Fix: stop smoke when building collapses

If building was hit quickly with many explosions smoke would rise
from nowhere. Now this smoke stops when the building collapses.
Merge branch 'Smoke' into InGame
Fix: createExplosionAndTrack changed visibility to public
Fix: Friendly missiles will not explode on collide with building

When friendly missiles come in contact with buildings they will not
explode. Explosions from friendly missiles will still harm buildings.