Add seed input

[HalfVoxel]

Instead of using the same hard coded seed every time a map is played it would be very useful for testing to be able to pass in a custom seed in a similar way as e.g the map name to use is passed in. Currently it can be tricky to determine if a new bot version is actually better than an old bot version (when testing locally) or if it just got lucky.

Right now the seed is hard coded to be based on the map seed.