zoomlevel, opacity, maxFeatures
with Stamen toner layer
color brewer YlGnBu palette
slider appearance
do not fetch/display use
color from selected year
removed Stamen added Cloudmade map layer
slider decoupling
update_screen simplify
removed ortophoto layers and associated code
layers default on, removed buttons on map
building_styler year to color mapping
play/stop button and animation
styling all around
layout tweaking
README update & package file