Melee creeps

[Clauvin]

Once #2 is finished, adding melee creeps shouldn't be hard:

• Pick a model and animations to represent melee creeps;
• Use previous spawn function to spawn melee creeps.
• Do a pass on creep code to better organize attribute info about creeps (damage, Max HP, speed, attack speed, armor, etc) in an easily accessible, readable and editable (not editable in the middle of a game, unless an appropriate - and visible by all players - option is toggled) way by the server;