Implement message compressor

[yoos]

It might be useful to implement a wrapper message type to compress and decompress floats and doubles in arbitrary message types. For example, a type consisting of four floats and an int8 might be compressed to five int8s or even four 4-bit fields and an int8.

Not sure how flexible this should be, but I can see this being useful for reducing bandwidth requirements over wireless (which is a downsampled data stream already, probably will ever be used for sanity checking the system from the ground.. decreasing data resolution shouldn't be a big deal)

[yoos]

This could be as simple as implementing half-precision floating point (dare we implement quarter-precision?)