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.
Typo in `rails-minor-mode-local-prefix-key' customization documentation.
Merge branch 'move-bindings'; added customizations for the
rails-minor-mode keymap prefixes.

Note: Unfortunately emacs-rails sets up the key bindings when the
library is loaded.  This probably speeds things up a little but has
two issues: the library can not be loaded during init (before
customizations are loaded) and changing the prefix key customizations
only take effect after forcefully reloading emacs-rails (or restarting
emacs).