[Urgent] fix for constructed stats

I just noticed that the constructed stats graph I released last time showed the win rates when playing AGAINST each class rather than playing AS each class. This was leftover from my initial reverse-engineering. This patch fixes that, and should be published as soon as it's convenient in order to avoid confusion.

I also started tweaking the recent constructed games page in anticipation of making the filters work and a few other minor improvements. For example, I may want to be able to say "show me all games that I played with any Mage deck" as well as being able to say "show me all games I played with X Mage deck". I should have this feature done by the end of the week, but likely sooner.

I'll try to make these pull requests much less frequent in the future.