I've gone and done something naughty. I've just bumped $wgVersion

I've gone and done something naughty. I've just bumped $wgVersion
to 2.0alpha.

*waiting for the gasps to quiet*

The subject's been broached before, and honestly, there's no compelling
reason not to bump it at this point. The comment's been made that we
should've done it after 1.9, but that didn't happen. So we're doing it now.