Updates dependencies to get tests running.
Renames the top level commit file.

This renames the top-level commit file so it will not collide with
the existing RBTree library.  I need this in order to use this
library in a Ruby 2.1 environment.
Replaces deprecated Enumerator.new with Object#to_enum.
Merge pull request #1 from mjbellantoni/rename_require_file

Rename require file and some other cleanup