Use homebrew::tap instead of plain exec

While setupping boxen for my desktop machine, `Exec[tap-homebrew-cask`]
failed for me, because it wasn't able to find `brew` anywhere in the
path.

Most of the times, you should explicitly specify the `path` option,
because people may override the default with `Exec { path => ['...'] }.

I worked around that, not by trying to guess the path in which `brew`
will live, but by using the `homebrew::tap` resource, which takes care
of it all.
Merge pull request #4 from gsamokovarov/master

Use homebrew::tap instead of plain exec
Change path for current check
Update repository name to caskroom/homebrew-cask
Merge pull request #11 from reducingwip/update-repository-name

Update repository name to caskroom/homebrew-cask
Merge pull request #10 from reducingwip/fix-current-path-check

Change path for current check
Make sure cask is installed before installing any package it provides.

Closes #7
Fix run method to work on first run
Merge pull request #15 from juniorz/install_ordering

Make sure cask is installed before installing any package it provides.
Merge pull request #17 from juniorz/fix_run

Fix run method
Merge from trunk
Merge branch 'master' of github.com:n0ts/puppet-brewcask

Conflicts:
	manifests/init.pp