Port Rails 3.2.12 fix for MySQL weirdness.

Should fix #219
Handle additional edge cases for MySQL workaround
Fix failing spec on 3.0
Add date to CHANGELOG
Remove orphaned debugging line
Revert MySQL hacks from 1.0.16
Don't treat nils as quotable. Fixes #221.
Fix deprecation notices
Actually, we don't need the branching
Sifters must be prefixed with sifter.

This is to eliminate confusion between sifters and scopes. They aren't
the same thing. Related to #142. Still on the fence about having the
sifter macro define a scope to match, but I'm leaning toward it being
too much unnecessary magic for now.
Add syntax highlighting to the readme
Merge pull request #234 from janko-m/readme-syntax-highlighting

Add syntax highlighting to the readme