Add contributing and remove hacking portion of README.
Allow 'feature switch' to switch by pull number using -n
Switch-by-number: Abstract logic and add to hotfix
Switch-by-number: update documentation
Switch-by-number: update man docs
Add 'iFixit' back into Ronn-generated files

Had to run 'ronn filename --organization=iFixit' to add it back
Improve flow of hotfix branch-switching logic
Merge pull request #92 from iFixit/switch-by-number

Allow 'feature switch' to switch by pull number
Merge add-contributing (#91) into master

Add CONTRIBUTING.md.

Remove the hacking section from the README and place it in CONTRIBUTING.
This takes advantage of github's nifty little feature that allows you to
view contributing rules when filing a new issue .
Merge branch 'master' into url-command