[O] [RFC] Proposal for rebindings in Org 8.3

[Bastien]

The purpose is to be polite with minor modes and to not use
C-c [:punct:] keybindings, as recommended in the Elisp manual.

This is related to the issues reported here:
http://lists.gnu.org/archive/html/emacs-orgmode/2014-01/msg00866.html
http://article.gmane.org/gmane.emacs.orgmode/82010

Here is a table to summarise the proposal:

| Key   | Command                           | Proposal         | Status |
|-------+-----------------------------------+------------------+--------|
| C-c # | Checkboxes                        | C-c x            | Free   |
| C-c ~ | Cooperation                       | C-c C-~          | Free   |
| C-c , | Priorities                        | C-c C-,          | Free   |
| C-c ? | Editing and debugging formulas    | C-c C-?          | Free   |
| C-c ! | Creating timestamps               | C-c C-!          | Free   |
| C-c . | Creating timestamps               | C-c C-.          | Free   |
| C-c ` | Built-in table editor             | C-c C-`          | Free   |
|-------+-----------------------------------+------------------+--------|
| C-c ' | Editing and debugging formulas    | C-c " or C-c C-' | Free   |
| C-c ^ | Structure editing, plain lists... | C-c C-^          | Taken  |
| C-c @ | Structure editing                 | C-c <            | Taken  |

The order is from the less problematic ones to the more problematic ones.

A few comments on the last three:

- " is not a punctuation character, I find C-c " instead of C-c ' good.

- C-c C-^ is taken by org-up-element.  I'm in favor of using C-c C-u
  (currently bound to `outline-up-heading') for `org-up-element'.
  Nicolas suggested C-M-u but I find it convenient to have it when
  editing Elisp code within Org buffers.

- C-c < is bound to `org-date-from-calendar', which inserts the
  current date (or the date from the calendar buffer) at point as
  an active timestamp.

  C-c > is bound to `org-goto-calendar' and goes to the calendar,
  going to the date at point if any.  This is just a slightly more
  contextual M-x calendar RET.

  So the whole suggestion here is:
  
  - in Org-mode, remap calendar to org-goto-calendar and unbind it
    from C-c >

  - use C-c > for `org-date-from-calendar'

  - use C-c < for selecting the whole subtree, which is consistent
    with the use of `<' as a speedy command for doing the same.

Let me know how you feel about such move in general and each rebinding
in particular.  We are not forced to solve them all at once.

Thanks,

-- 
 Bastien