Implement an AI

[mabre]

• AI base class or interface
• simple AI which can aim at enemies,
• considering range of projectiles,
• considering obstacles,
• considering wind [a bit],
• choosing appropriate weapon
• not hurting friends
• move to better position
• jump
• collect supply drops [only nearby]
• have different levels of AIs [dummy and simply for now, open new issue for other types]
• add UI for playing against AI (maybe only 2 player local game for the beginning—we might change the way how teams are associated with players in the future anyway)
• network game

[mabre]

@Jessypet Please add a possibility to choose between Human and Computer (Simple) for each team in local game (ai branch). Add an aiType type property with value set to AIType.NONE.getValue(), or AIType.SIMPLE.getValue(), respectively. If you want, you can also implement reading the property in MapWindow (in line 206 is a temporary implementation which assigns a simple AI to every but the first team).