Please add the ability to export/import color schemes

[alanmies]

I'd be perfectly happy if I could just get that same config format used in the template definition file copied to my clipboard, so I could replace that part in the file and continue working on a theme. Naturally something like serializing to JSON would be even much better.

But I'm a man of modest needs. I'd for now be happy just if I could know all the variables you can give as "ionic colors", because the example theme on the official web site certainly doesn't include everything. And it sucks, because values not defined in a theme get default values when applying a new theme, and it can be quite annoying if you just got them right, or at least better.

(perhaps I'm just stupid, but for example I can define button colors in a theme, or know the syntax for it from the docs - but how do I specify the colors for say a "positive" button, is that even possible?)