Added gradle wrapper so no local gradle installation is required and the used
gradle version can be set by the build file.

added gradle build file

Read additional info from API.

Features for Getting Groups, Group Membersm Creating Groups and Creating Projects

Read the `milestone_id` & `description` being returned as part of the API enhancements.

Do not hide underlying SSL message, helps with siagnosing problems, e.g. SSL problem might not be in cert exactly, but in mismatched host-name

Add httpUrl property

Support merge requests from a different project (fork) in getCommits()

fix maven compiler plugin bug

getNamespaceMembers and getCurrentSession

Issues, ProjectMembers, and notes (for issues, not just MergeRequests)

method