should address #33
includes cleanup and tests
i'm not crazy about leaning on installing/uninstalling caffeine in the
tests. it makes for some unnecessarily heavy tests and downloads. but
i'd rather get tests in place first then fix the warts.
I chose Caffeine since it's relatively small to download. Eventually I'd
like to switch this up so we bundle a dmg, zip, etc that the test suite
wires in to verify that we do the Right Thing (tm) with all those file
types. Probably will want to support `file://` URLs in Casks to help us
for that use case.
phinze