Change the Action Lists format so that it uses keywords instead of the English strings

Right now the action list file format uses the English string of the action/option, e.g. "'Force Background Colour': u'true'". It uses the English string so that you can change the language and it will keep working.
It should instead use a keyword so that we can change the strings, and so that we can get rid of the _t(phrase) method.

We should also make this backwards-compatible.