zap stanza from mackup for slate.rb
zap stanza from mackup for soulver.rb
zap stanza from mackup for sourcetree.rb
zap stanza from mackup for spark.rb
zap stanza from mackup for spectacle.rb
zap stanza from mackup for spotify.rb
zap stanza from mackup for sublime-text.rb
zap stanza from mackup for superduper.rb
zap stanza from mackup for textmate.rb
zap stanza from mackup for tower.rb
zap stanza from mackup for transmission.rb
zap stanza from mackup for transmit.rb
zap stanza from mackup for twitterrific.rb
zap stanza from mackup for viscosity.rb
zap stanza from mackup for witch.rb
zap stanza from mackup for xld.rb
doc nit; missing prompt character
double slash in zoomus
add uninstall :rmdir

per discussion at https://github.com/caskroom/homebrew-cask/pull/6174#discussion-diff-17516171
refs: #6174

This PR is large because of some test-suite refactoring.
support `brew cask --version` per `USAGE.md`

closes #6178