Reviewing the multitouch branch

[Matthias Clasen <matthias clasen gmail com>]

There is a ton of stuff in the multitouch branch, and I really want to
make progress on getting all this good stuff merged at the hackfest,
so I think we need to start reviewing the branch before we get
together. Since there's so much stuff in there, I'll try to split this
up in a series of mails, discussing subsets of the API. Feel free to
chime in, I don't claim to be an expert on input handling, so I may
get things wrong or overlook issues...


Matthias