Removed the term "Lua", because users were turned off by something they didn't understand.
A special-case Lua script ("Shortcut") allows the user to select an arbitrary Action.
The "Shortcut" script is selected by default, and in this case there is no "Type" or "Author" displayed.
Action-Buttons may still trigger Lua scripts, as a secondary function.
* register bindings for action_param
* honor pre-seeded value (don't ask)
* allow to pre-seed a script-name
* allow to cancel interactive script load at parameter-stage
