Replaced Unirest with OkHttp (#349) Rest in peace Unirest, you served us well (most of the times) Things that were changed with this PR: - Replaced Unirest with OkHttp - Added v6/ to the base api route - Deprecated JDA#shutdown(boolean) - Refactored argument checks to new Checks class - Changed how query parameters are handled - Exposing RequestFuture to the public - Added HttpRequestEvent for debugging - Updated README.md (commit: 5a54243)