Rewrite of code to generate 'list' property for shortcuts

[ghost]

Changes to code to generate 'list' property - supercedes #16, as discussed @14b215dd08

• Cleaner code, splitting on commas to grab appropriate part of the shortcut
• Only works for ActivateWindow shortcuts (other shortcuts will return as-is - let me know if there are any other shortcut types that should provide a specific 'list' property)
• Moved to datafunctions.py (because I intend to use this for updated widget selection code, and because xmlfunctions has become out of control and code needs moving out of there!)

@marcelveldt - this is your feature, so can you please review to ensure I haven't broken the use case you originally added this for.
@HitcherUK and @Nessus85100 - both of you reported issues with the original code, so can you please test to ensure the code fixes any issues / does not introduce any new issues / there's no other obvious use-cases I should add whilst I'm working on the code.

Cheers.

[marcelveldt]

@Ignoble61, It looks fine to me. Great thing too about changing the widget selection, that is something that is really wanted/needed.
atm I used a very complicated workaround for that in my skin, would be good if that could be replaced by this.

This request btw came from @HitcherUK Maybe he can tell us a little more about the use case he wants to use this list property for. I suspect it has something to do with choosing widget content. In that case the new widget selector would be even better.

[marcelveldt]

code working fine on my testsetup

[ghost]

Thanks for testing + merging 👍

[Nessus85100]

Also everything working fine for me too. The missing bracket it's fixed.