Add drupal-drush-sql-cli command

[joddie]

This adds a command and keybinding to run drush sql-cli in a properly set-up Emacs SQL buffer.

This is fairly lightly tested (e.g., I have not tried using it with anything other than MySQL) so feedback is welcome.

[arnested]

This looks very interesting!

Just tried it out very shortly myself and it works with mysql as well for me. I think I'll just merge it and then we'll see if we get reports from other database backends. It's not like it is breaking other functionality.

In my setup I have no database prompt in sql-interactive-mode but that is not related to your code - it even happens with emacs -Q.

I also have some encoding stuff that's not right (the content in the database is not show with the right encoding). That's not a problem when connecting M-x sql-mysl directly to the database but the problem could possibly be in some of my other configuration. And I don't think of it as a show stopper for getting this awesome feature out in the wild and gather feedback.