should take care of #104
this was a subtle one - after i reorganized the requires, plist/parser
was getting double required, which broke plist parsing and hence dmg
installs
this delegates to homebrew's uninstall to get its work done. vanilla
`brew uninstall` actually works, but this gives us a more consistent
interface.
as discussed in #47
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.
phinze