Start implementing multiprocessing in offling compress
Implement a simple process pool to limit the concurrent process count
Add another queue so errors get passed from the worker to master process correctly
Completely disable multiprocessing when max_processes == 1
Catch ImportError importing multiprocessing and completely disable it
Remove stray multiprocessing import, warn user if multiprocessing not available and they requested it
Start tests for multiprocessing, still need to actually verify it was used