merge and lossless compression tests

[cj-mclaughlin]

• Initial tests (recover fixed transformation) for map merging methods moved into coms
• Compression methods (run-length-encoding and quadtrees) moved into coms, along with tests
  • Note that for the time being I have included the 'mapsize' as an argument passed into the `decode` methods, meaning this will have to be sent as a header to the merge message if we are to use compression.
  • Also keep a careful eye on the data types, as quadtrees/RLE are not uint8, as in the maps they represent.

[tylerferrara]

We have yet to populate msg.Merge with anything, so feel free to modify it to your liking.