Work to improve drafts folder management (fixes NB#56483).

Work to improve drafts folder management (fixes NB#56483).
* src/widgets/modest-msg-edit-window.h:
        * Now the message data contains the draft message the editor was
          created from, if any, and the account name of the From: email
          address we'll use.
* src/modest-ui-actions.c:
        * Now it retrieves the account name from the editor to be able
          to send the message from local folders.
        * Now it retrieves the draft message on trying to send a mail,
          to be able to delete it on send.
        * Now it retrieves the draft message on trying to save to
          drafts, to delete it and replace it with the new edited
          version.
* src/maemo/modest-msg-edit-window.c:
        * Obtains the account name and adds a reference to the drafts
          message on getting message data, to be able to handle sending
          on local folders, and removing drafts that should be removed.
* src/modest-mail-operation.[ch]:
        * Now send new mail removes the draft message the mail is coming
          from, if any.
        * Now save to drafts removes previous draft message if any.
* src/modest-main.c:
        * API update on send_new_mail method.
* src/dbus_api/modest-dbus-callbacks.c:
        * API update on send_new_mail method.

Other fixes:
* src/widgets/modest-msg-edit-window-ui.h:
        * Added non implemented actions for global search and find in
          page.
* src/maemo/ui/modest-msg-edit-window-ui.xml:
        * Add ui manager actions for find in page and global search.
* src/maemo/modest-msg-edit-window.c:
        * Some changes on font size update code.

pmo-trunk-r2061