mine collisions

added a mine controller to check for mine collisions
also mine explosions now do damage
Merge pull request #339 from BU-CS673/pmd-261

Pmd 261
unit tests for mines

unit tests for mine collisions and spawn entities
warning

removed warning
Merge branch 'production' into pmd-mines

Conflicts:
	bubolo/src/bubolo/world/entity/concrete/Tank.java
Merge branch 'production' into pmd-mines

Conflicts:
	bubolo/src/bubolo/graphics/SpawnSprite.java
	bubolo/src/bubolo/world/entity/concrete/Tank.java
fixed merge conflicts

also added fuse to mines

mines are removed from tiles after explosion
Merge pull request #340 from BU-CS673/pmd-mines

Pmd-mines -> production