Replace "C-c" with "C-c ," and "C-c C-c" with "C-c , ,"

This change also allows separate configuration of the "local" and
"global" prefix sequences.

This means /most/ of the key bindings are now in accordance with the Emacs key
binding Conventions by default.

http://www.gnu.org/software/emacs/manual/html_node/elisp/Key-Binding-Conventions.html
http://www.gnu.org/software/emacs/manual/html_node/elisp/Keymaps-and-Minor-Modes.html

 You can set `rails-minor-mode-local-prefix-key` to "C-c" and
`rails-minor-mode-global-prefix-key` to "C-c C-c" if you want to
retain most of the original key bindings.