Implement Unit managment

[arves100]

Packets that works with this does not exists, and some things are actually lacking in order to work.

No Unit definition MST is loaded from the server yet, that would be the first possible step to implement anything unit related.

Specifically, in the first game I belive it would make sense to implement:

• Fusion
• Selling
• Squad management (normal units only, no arena)
• Evolution

Items, Elgyphs, and so on would be handled later.