Code formatting

So here's one of those large auto-formatting commits. I only intervened in small parts; 99% of this is an auto-format. I included everything under the ```com.ichi2``` package but skipped libanki -- I'll go through that some other time.

Hopefully this doesn't interfere with anybody else's work. On the bright side we won't have these formatting problems getting in the way any more, but we do need to be strict about what gets merged before it degenerates into this state again.

A few things:
- This commit does not format any XML.
- Mass-code-formattings kind of mess up git blame. We'll consider this a necessary evil.
- I removed a few more unused imports while I was at it.