Merge pull request #15 from Arcterus/master

Rename to pacapt and add -Qo option for Homebrew

TODO:
* Add a note about the change to README
* Add tip for user who wants 'pacman' as executable name
Merge pull request #16 from Arcterus/master

-Qo now works with relative pathnames on Homebrew
Merge pull request #17 from Arcterus/master

Add -Rss option for Homebrew and Zypper
Add support for macports
Merge pull request #18 from 10sr/portsupport

Add support for macports.
Make the Homebrew paths more portable