Merge pull request #5 from lexwebb/master

Merge of Mines code
Merge pull request #6 from lexwebb/master

Mines!
Changed the way MinBlock and MaxBlock methods work, added static instance list of Mine class.

Added functionality to the add() and remove() methods, so that they add and remove the Mine instance from the static list.
Moved LoadMineTask to the mines package, out of Main.java.
Rename LoadMinesTask to LoadMinesTask.java
Moved LoadMineTask to the mines package, out of Main.java.
Merge pull request #3 from GoldRushMC/master

Changes to the mine class and mine task.