[coretasks] Fix a case issue in privilege list

I think, anyway. Perhaps. We'll see. It's relevant to issue #365, but
I'm not confident it fixes it. With this change, the example given
doesn't cause an error. So that's something.
[core] Use Nick objects for channels more often

May also have an effect on #365, but who really knows.
[github] Fix #416
[currency] Add Bitcoin as a currency
[tell] Unicodification

Should fix #399
[calc] Account for silly non-Anglophones

Fix #435
Merge pull request #433 from BOFHers/nache_dev

Allow you specify lang on wikipedia command
[core] Use coding and unicode_literals consistently

Also add them to CONTRIBUTING. Both are now official style guidelines of
the project. Anyone who pushes new code without them will be
defenestrated.