Code Quality Improvement - @Override annotation should be used on any method overriding (since Java 5) or implementing (since Java 6) another one

Added create groupViaSudo and getGroupMembers

update from timols/java-gitlab-api

commit comment creation and listing added

Added import_url param to createUserProject

Resolves #93: Fixes pagination issues with find users

Type checking and error message improved

Added a descriptive IllegalArgumentException message.

Adds pagination support and branch parameter for commit API

Corrects an issue in which GitlabAPI.findUsers returns the first default
page of users when the emailOrUsername argument is null or empty.

Adds CRUD support for labels

Adds create / edit support for milestones

Wraps "POST", "GET", "PUT" and "DELETE" HTTP verbs for api version 3.

Wraps "POST" and "PUT" verbs for creating and updating milestones
in api version 3.

Expose HTTP Code through GitlabAPIException

Implement Authentication via an HTTP Header 

Add method to delete a branch

Add method to retrieve merge request changes

Add missing fields to GitlabProject