added zoom/pan to non square pixels demo
added zoom/pan to non square pixels demo

antoinepairet/cornerstone,google/cornerstone,cornerstonejs/cornerstone,cornerstonejs/cornerstone,FilippiSilva/cornerstone,chafey/cornerstone,FilippiSilva/cornerstone,adreyfus/cornerstone,chafey/cornerstone,cornerstonejs/cornerstone,liyocee/cornerstone,adreyfus/cornerstone,liyocee/cornerstone,cornerstonejs/cornerstone,adreyfus/cornerstone,swederik/cornerstone,google/cornerstone,antoinepairet/cornerstone,swederik/cornerstone