Feature: Multitouch / Gesture support

[tribal-tec]

Support basic gestures to perform several actions:

On items:

• [x] Pan: move content
• [x] Pinch: resize/zoom content
• [x] TapAndHold: (de-)select content
• [x] DoubleTap: toggle 1to1/fullscreen size
• [ ] Tap: tbd
• [ ] Swipe: tbd

On view:

• [ ] Pan: tbd
• [ ] Pinch: tbd
• [ ] TapAndHold: tbd
• [ ] DoubleTap: tbd
• [ ] Tap: tbd
• [ ] Swipe: tbd

[tribal-tec]

Working on it, separate working branch will be squashed to master