[WIP]adding mobile touch support this is a bit messier than it looks

[kmader]

adding hammerjs to dependencies
Fixes #2

https://mybinder.org/v2/gh/chestrays/cornerstone_widget/hammerjs?urlpath=apps%2Fnotebooks%2Fdemo.ipynb

[codecov-io]

Codecov Report

Merging #3 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master       #3   +/-   ##
=======================================
  Coverage   97.05%   97.05%           
=======================================
  Files           3        3           
  Lines          34       34           
=======================================
  Hits           33       33           
  Misses          1        1

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[kmader]

The other issues are to then replace and complement current tools with manually selected ones. It probably makes more sense to have a cornerstone and cornerstone mobile widget?
https://github.com/cornerstonejs/cornerstoneTools/blob/master/examples/alltouchtools/index.html

var configuration = {
        testPointers: function(eventData) {
            return (eventData.numPointers >= 3);
        }
    };
    cornerstoneTools.panMultiTouch.setConfiguration(configuration);
    cornerstone.loadImage(imageIds[0]).then(function(image) {
        cornerstone.displayImage(element, image);
        // Set the stack as tool state
        cornerstoneTools.addStackStateManager(element, ['stack']);
        cornerstoneTools.addToolState(element, 'stack', stack);
        cornerstoneTools.touchInput.enable(element);
      
        // Enable all tools we want to use with this element
        cornerstoneTools.zoomTouchPinch.activate(element);
        //cornerstoneTools.rotateTouch.activate(element);
        cornerstoneTools.wwwcTouchDrag.activate(element);
        cornerstoneTools.panMultiTouch.activate(element);
        // helper function used by the tool button handlers to disable the active tool
        // before making a new tool active
        function disableAllTools() {
            cornerstoneTools.panTouchDrag.deactivate(element);
            cornerstoneTools.rotateTouchDrag.deactivate(element);
            cornerstoneTools.rotateTouch.disable(element);
            cornerstoneTools.ellipticalRoiTouch.deactivate(element);
            cornerstoneTools.angleTouch.deactivate(element);
            cornerstoneTools.rectangleRoiTouch.deactivate(element);
            cornerstoneTools.lengthTouch.deactivate(element);
            cornerstoneTools.probeTouch.deactivate(element);
            cornerstoneTools.zoomTouchDrag.deactivate(element);
            cornerstoneTools.wwwcTouchDrag.deactivate(element);
            cornerstoneTools.stackScrollTouchDrag.deactivate(element);
        }