Ensure that all uncaught exceptions are printed by build's end.
Remember to set this.persistent when --watch provided.

--whoops
Adopt a simple, unambiguous CLI usage syntax.

Usage: commonize [options] <source directory> <output directory> id1 [id2 [id3 ...]]

How righteous this syntax seems in retrospect!
Add comments and an example processing step to bin/commonize.
Remove Brigade tests that are no longer applicable.
Update README.md and bump version to 0.5.0 in preparation for NPM publishing.