Allow an input key do be specified instead of using ergoemacs-read.
This allows a test for Issue #138 that doesn't require waiting for
unread-command-events to be parsed.
Added ergoemacs-describe-key
Add better test for Issue #138.
Make sure ergoemacs-describe-key is turned off after
ergoemacs-undefined is called.
Remapped describe-key to  ergoemacs-describe-key.