[evince] Gesture support

[Jussi Pakkanen <jussi pakkanen canonical com>]

Hi

The touch team at Canonical has been working on gesture support for
Evince. The next release of Ubuntu will have a fully gesture enabled
Evince, supporting pinch-to-zoom, rotations and so on. If you want to
try it, the easiest way is to download a daily ISO of oneiric and run
it. (Though it was broken yesterday, and I'm not sure if the fix has
gotten to the daily builds yet.)

We have a patch for Evince gesture support that is quite well isolated:
all code dealing with gestures is #ifdef'd out. If there is interest, we
would like to offer help getting it upstream.

The gesture framework it uses is libgrip, which is a gesture helper
library on top of GTK+. The reason for this is that GTK proper does not
have native gesture support and probably won't have for quite some time.
Libgrip is platform-agnostic but currently the only backend is the
uTouch stack on Linux.

Thanks