Remove deprecated download APIs
Reorganize unimplemented.*.yml
Implement AuthenticatedUser.get_user_issues and Organization.get_issues
Make special case in code generator for previous commit
Github.get_hooks and .get_hook (+ some tests)
Fix symlink in git-objects

Creating a git tree with 'content' doesn't respect 'mode'. Issue
opened to GitHub.
Make Dir an inner class of Repository

Because its url doesn't allow .update
Fix symlink

In setup_enterprise_test_resources.py, add "\n" to the contents
of the symlink to make GitHub return type="symlink" in
testGetRootContents_allParameters.json
Add tests for Repository.get_contents
Add tests for SymLink
Add tests for File
Add tests for Submodule