This lets us get rid of a few more calls to Error(), and it simplifies things
for clients of OnWorker: they can simply return an error from their callback
like we do everywhere else.
I've been thinking about this for a while: I think it looks really cool if nuking your working tree
actually results in a nuke animation.
So I've added an opt-out config for it
We have not been good at consistent casing so far. Now we use 'Sentence case' everywhere. EVERYWHERE.
Also Removing 'Lc' prefix from i18n field names: the 'Lc' stood for lowercase but now that everything
is in 'Sentence case' there's no need for the distinction.
I've got a couple lower case things I've kept: namely, things that show up in parentheses.
