add 'above' and 'below' reordering options for compositing layers
allow user-specifed ArcGIS sublayer excludes
add default parameters for ArcGIS servers
handle empty array correctly in one_or_many
only reorder layers of updated sources
correctly handle ArcGIS services with spaces in name
use built-in REXML::Child#remove instead of delete_self
change arguments for rerender method
refactor ArcGIS rerendering
refactor stroke-dasharray scaling