v0.15 - Bearded Hijinks

• New: IRepositoryContentsClient.GetAllContents now has an overload to support specifying a reference - #730 via @goalie7960
• New: Support for retrieving rate limit information from IMiscellaneousClient - #848 via @Red-Folder
• New: Use GitHubClient.GetLastApiInfo() to get API information for previous request - #855 via @Red-Folder, @khellang
• New: PreviousFileName returned to show renamed files in commit - #871 via @CorinaCiocanea
• Improved: CommentUrl returned on Issue response - #884 via @naveensrinivasan
• Improved: Issue and Code Search now accepts multiple repositories - #835 via @shiftkey
• Improved: Search now accepts a range of dates - #857 via @ChrisMissal
• Improved: Documentation on Issue response - #876 via @Eilon
• Improved: Code Search now accepts FileName parameter - #864 via @fffej
• Fixed: GetQueuedContent should return empty response for 204 No Content, instead of throwing - #862 via @haacked
• Fixed: TeamClient.AddMembership sends correct parameter to server - #856 via @davidalpert
• Obsolete: Authorization endpoint which does not require fingerprint - #878 via @niik

Breaking Changes:

• #835 has changed the Repos property for SearchIssuesRequest and SearchCodeRequest
  are now of type RepositoryCollection so that multiple repositories can be searched.
• The workarounds removed in #878 were added initially to support transitioning, but now
  we enforce the use of a fingerprint. See https://developer.github.com/v3/oauth_authorizations/
  for more details.