Change mines to damage and burn agents instead of instantly killing them

[tommy33790]

Instead of instantly killing the agent picking up a mine, they should instantly suffer 50% damage (value is up to balancing) and keep burning after the explosion. While burning, an agent slowly looses energy until the fire is 'put out' by another team agent.
The lingering fire damage could depend on the number of agents a team has, to make up for the number of agent that are available for putting out the fire.
In addition to Issue #10 nearby agents could suffer max 25% damage without burning. Again, final values would depend on balancing.