Implement Search API

Add code and test for the -legacy- search api;

    http://developer.github.com/v3/search/

Issue #1
Merge pull request #11 from suapapa/master

Implemented Search API
Merge branch 'master' into user-endpoints
Implemented the GitHub.AddEmails() function.
Added some more private "tooling" functions so that we could easily make
POST requests.