Fix bug preventing specifying other params when listing

Previously, e.g., Project.files(ref_name='other_branch') wouldn't work.
Add extra actions in GitLab to class, not instance
Fix Project.hooks() API

Wasn't working previously due to a missing url
Fix Project.get_branch()

Branches use 'name' as the key field instead of 'id'
Populate gitlab3 namespace with the generated core classes
Allow decorators for the extra action functions

Can write a 'wrapper' decorator in action definition to handle the
more obscure cases.
Allow passing branch obj to [un]protect_branch, update branch obj w/new state

Project.[un]protect_branch() will now accept either the branch name
or a Branch object.

The Branch's 'protected' field is now updated when calling either.
Make gl.add_project_for_user() return a Project object

Now matches return type of other add functions
Add get_<obj>(id) functions sans 'get_', i.e. <obj>(id)

I find myself wanting to use gl.project(id) more than gl.get_project(id)
Update docs
Bump version to 0.2