rebar/rebar — pull request #274 by redpine50 (2014-05-07 17:15:20+00:00)
Title: Use lowercase for Windows drive name to resolve issue #250

On windows, bootstrap.bat failed with next error.
Command 'escriptize' not understood or not applicable

This happens because the drive name in path got from rebar_utils:get_cwd() and base_dir(Config) are different case.
Made the drive name the same lowercase using filename:absname().