[dev/m42][uBrowser] One point touch.

[dev/m42][uBrowser] One point touch.

Up to now, single point gestures (including panning, fling,
clicking) were handled through a Mouse->to->Pointer
events conversion solution. It happens on the RWHVEfl level,
and benefits both EWK and content apps.
However, multi touch gestures (e.g. pinch zoom) were not functional.

Patch fixes that by start listening to EVAS_CALLBACK_MULTI_{DOWN,MOVE,UP}
events, and forward them to chromium's (Aura) the existing gesture
recognition machinery to get them handled.

Bug: http://107.108.218.239/bugzilla/show_bug.cgi?id=12716

Change-Id: I1662c611af8ceba5ba20398adbad9b9bb5ada844
Signed-off-by: Antonio Gomes <a1.gomes@samsung.com>