bugfix: numberOfDataSetsCached was undefined, because loadedDataSets is an Object (not an Array)
bugfix: numberOfDataSetsCached was undefined, because loadedDataSets is an Object (not an Array)

cornerstonejs/cornerstoneWADOImageLoader,chafey/cornerstoneWADOImageLoader,google/cornerstoneWADOImageLoader,chafey/cornerstoneWADOImageLoader,google/cornerstoneWADOImageLoader,google/cornerstoneWADOImageLoader,cornerstonejs/cornerstoneWADOImageLoader,cornerstonejs/cornerstoneWADOImageLoader,chafey/cornerstoneWADOImageLoader