Homebrew/homebrew-bundle

Improve style of `conflicts_with` implementation.

Unlink and stop service for conflicting formulae.

Unlink and stop the service for conflicting formulae or those specified
by a `conflicts_with` argument. This is useful when using `brew bundle`
to manage the transition between e.g. `homebrew/versions` versions.

Fix ruby issues

restart_service only if formula installed or upgraded

Check for Brewfile existence before doing any work

Require bundler explicitly

Use the same time format for parsing commit.

Massively speedup `brew bundle check`.

The main slowdown with `brew bundle` check was the repeated shelling out
to other `brew` commands unnecessary. We can't avoid this for
`brew cask` (for now) but we can do so for the others. Additionally
now that `brew bundle` and `brew services` are core commands we don't
need to check if they are installed and we don't need to check if
Homebrew is installed (as it's require for `brew bundle` to work).

As well all this: rename specs to be more consistent.

BrewDumper: handle bad keg JSON more strictly.

If we didn't get a keg back then ensure we don't try to read it in any
form. Also, tweak how we read it so bad or missing data won't make it
explode.

check: speed up by checking less.

We’ve been doing more checking here than is strictly necessary to
verify. Unfortunately the slowest case is everything being fine and
it’s really hard to improve as they processes we shell out to are slow.
I’ve tried speeding this up with `Thread`s and async `IO.popen` but
neither actually improve things. Further speedup will have to happen in
those commands instead.

Rename command to `brew-bundler.rb`.

This means it'll use the Homebrew Ruby rather than whatever Ruby is in
your path. This also means if you're using it to e.g. install some
project dependencies to install a Ruby that does not already exist then
you do not need to do e.g. `RBENV_VERSION=system` first.

brew_dumper: handle missing keg in JSON.

Closes #121.

Support aliases.

Also some other general cleanup and refactoring and ensuring that tests
have 100% coverage.

Cask args final

Don't use reserved keywords

Don't warn on empty `brew cask list`.

Fix shebang so brew bundle works on Linux

Cleanup and tweaks