Add ability to do conditional requets as described [here](http://developer.github.com/v3/#conditional-requests)
Add ability to do conditional requests to save api calls
Add ratelimit header.
Merge remote-tracking branch 'piascikj/master'

Conflicts:
	api/v3.0.0/authorization.js
	api/v3.0.0/events.js
	api/v3.0.0/gists.js
	api/v3.0.0/gitdata.js
	api/v3.0.0/issues.js
	api/v3.0.0/markdown.js
	api/v3.0.0/orgs.js
	api/v3.0.0/pullRequests.js
	api/v3.0.0/repos.js
	api/v3.0.0/routes.json
	api/v3.0.0/search.js
	api/v3.0.0/statuses.js
	api/v3.0.0/user.js
Merge commit '1979ad4'

Conflicts:
	api/v3.0.0/authorization.js
	api/v3.0.0/events.js
	api/v3.0.0/gists.js
	api/v3.0.0/gistsTest.js
	api/v3.0.0/gitdata.js
	api/v3.0.0/issues.js
	api/v3.0.0/markdown.js
	api/v3.0.0/orgs.js
	api/v3.0.0/pullRequests.js
	api/v3.0.0/repos.js
	api/v3.0.0/routes.json
	api/v3.0.0/search.js
	api/v3.0.0/searchTest.js
	api/v3.0.0/statuses.js
	api/v3.0.0/user.js
	index.js
	package.json