* add project statistics information to Project model

* fix update user bug.
`skip_confirmation` should be `skip_reconfirmation` when updating user.

* Load forks of a project with Pager
* Load comments of a commit with Pager
* Load merge request changes
* Load merge request participants.
* Method to request repository contributors
* getMergeRequestChanges method needs list of diffs
* Fixed getFile method does not handle spaces in path correctly

* add extern uid field for create
* added fluent builder pattern to User