All modules now expose their actions as public static constants
Issues: The menu module no longer closes when an item is clicked (before
it would intercept any executed command and look if it matches one of
its exec commands)
Action strings now have the form '#MODULE#ACTION'
For example to trigger the action 'toggle' in the 'module/date' module
one would now use '%{A1:#date#toggle:}'
With this action strings can now be uniquely assigned to one module.
Fixes#1172
