Fix zoom in/out with buttons. Closes #93
Fix zoom in/out with buttons. Closes #93

This commit uses openlayers 3 to zoom in/out with the mouse wheel and trackpad,
as well as with too extra buttons. Additionally, it shows a Copyright notice
about the picture, linking it directly with the Flickr page of the photo.

MicroPasts/drawB16,MicroPasts/NewForest-GermanPOW,MicroPasts/BAI-draw,MicroPasts/NFPA-SetleyNews2,MicroPasts/bronzeAgeIndex,MicroPasts/NewForest-GermanPOW,ahb108/ricepops1,MicroPasts/bronzeAgeIndex,MicroPasts/NFPA-SetleyNews2