jQuery 3.0 support, new options, shave 300 gzipped bytes

• jquery.panzoom 3.0+ adds support for jQuery 3.0 (version number parity is coincidental). This included removing the jquery.event.pointertouch plugin–it broke since the event extension API had changed. The result was mainly that the originalEvent property got used more often.
• I dropped support for pointer events because of pointer event issues in IE11. They weren't really adding anything and users were disabling pointer event support through hacks.

New features

1. contain: 'automatic' option. Greatly simplified contain option logic in the process.
2. disableXAxis and disableYAxis options.
3. panOnlyWhenZoomed option
4. exponential zoom option - Zoom increments exponentially rather than linearly. This is somewhat experimental, but still enabled by default. Linear incrementation was just too slow.

Notable bug fixes

1. Fixed an issue where rotations with negative values were getting reset to 0.
2. Moved backface-visibility:hidden style to parent to avoid blur on SVG images, but still promote the animation to its own composite layer for optimal performance.
3. IE11 had a false positive on a feature test for the input event. IE11 now uses the change event fallback.

Full 2.0.6 to 3.1.1 changelog