Update README.md

The original instructions provided by the creator are a bit confusing for those new to the Mac OS (like me). Provided an alternate method. Used http://stackoverflow.com/questions/7808452/what-is-the-full-path-to-the-packages-folder-for-sublime-text-2-on-mac-os-lion as additional reference.
Merge pull request #2 from geovanimartinez/patch-1

Update README.md