Moved away from poorly named username and repo to repoOwner and repoName
Removed unnecessary .ctor
Set HttpClient to proper lifecycle
Refactored GitHubService for testability and ease of use

Refactored GetPullRequests

Refactored SetCommitStatus

Refactored GetCollaborators

Refactored GetRepository

Refactored GetRepositories

Refactored GetUser
improved global nav
Added logo to design
Removed output caching for now