Last night TechCrunch reported that, according to an unnamed "source briefed on the matter," HP had stopped development of the Slate in its tracks, killing off the project entirely. Why? Well, according to the source, HP isn't thrilled with Windows 7's performance on the tablet. The Slate -- which was officially unveiled in January by Steve Ballmer himself -- had a rumored price of $549, and was supposedly launching in June. So, wha