RCF: better shortcut facilities

[jonathanBieler]

This solves a couple of issues:

• It makes it a bit easier to create keyboard shortcuts and to check them against events.
• It checks correctly shortcuts, taking into account CapsLock and such.
• It introduce platform dependent Modifiers (PrimaryModifier and SecondaryModifer) so you can have consistent shortcuts between windows/linux and OS X (PrimaryModifier refers to Control on windows and Command on OS X).
• It checks correctly (I think) the Command key on OS X (which is also the Meta key by default).

[yakir12]

Too bad this hasn't been merged yet, I sure could use this now...

[tknopp]

@yakir12 would you like to get commit access so that you can merge yourself? There are currently 0 maintainer, thats the issue.

[yakir12]

@tknopp, PM you on Discourse.

[tknopp]

@jonathanBieler: should this be merged?

[jonathanBieler]

I think it would be nice yes. That said I'm not super convinced by doing(Shortcut, event) (I had an Action type before that made more sense with doing) but I can't think of a better name right now (isshortcut isn't nice).