Update alfred recipe

Alfred is no longer distributed as .dmg but instead as a zip file.
Update Google Chrome checksum
Update Dropbox checksum
Parametrize Firefox recipe

Also update the checksum.
Update HipChat recipe to install newer version
Update LastPass checksum
Parametrize Skype recipe

Also update the version.
Update VLC version
Add dock largesize setting
Parameterize Safari preferences recipe
Update iTerm2 download link
Stick symlinks for rubymine preferences into 6.0 directory now.
Removed old flux attributes
pivotal_workstation is osx only, remove non-osx branches
Avoid anti-pattern of checking platform in osx-only cookbooks
Update homebrew repo URL
Merge pull request #221 from ryanhanks/update_homebrew_repo_url

Update homebrew repo URL
Merge branch 'master' into update-alfred-recipe
Use Homebrew Cask for Alfred
iTerm2 recipe uses Homebrew Cask