API & Documentation site

Hey,
As discussed in the mailing list, this pull request aims to relocate the API & Documentation currently in the GitHub Wiki to be accessible from phantomjs.org, with users encouraged to contribute improvements to each page.

Details on how to maintain the gh-pages branch can be found in it's CONTRIBUTING.md file.

Please let me know of anything else I can do to help.

Thanks,

Jamie, @GotNoSugarBaby