Added GetBranches method
Return a more helpful error message in the event of a 404 due to an invalid refs path.
added documentation to get branches
Merge remote-tracking branch 'upstream/master'

Conflicts:
	Octokit/Helpers/ApiUrls.cs
FixProjects
Merge pull request #270 from goalie7960/master

Added GetBranches method
Merge pull request #288 from alfhenrik/helpful-exception-on-invalid-input

Return a more helpful error message if an invalid refs path is provided
replaced all usages with v3 Accept header
Merge pull request #291 from octokit/tidy-up-releases-header

Deprecate custom Releases Accept header
Refactor SearchIssuesRequest to match the API