A bunch of l10n cleanup

I did a few things:

* convert %s to {name} because the latter is easier on localizers and
  gives more context regarding what the data is

  plus it allows the localizer to change the order of the variables
  which is really important in strings that have more than one variable

* add gettext calls around strings that should have them

* convert " to ' in a bunch of places

* fix some indentation where my editor (Emacs) fixed it

* add a few TODO items for things that I'm pretty sure don't fly
  l10n-wise

The ramification of these changes is that any project that has these
strings translated will now have to retranslate a bunch of them because
I changed the variable format. Sorry about that.