Add skeleton for SLD parser
Add scale to/from resolution calculations
Add initial pass of write support, always write out ol.style.Stroke as  LineSymbolizer
write out string concatenation in the more common way
Add more changes to the  halo functionality, introduce SLD defaults for symbolizers conform the SLD spec
add name and title to ol.style.Rule
get rid of the readers we don't support in ol3 symbology as yet
better write support for PointSymbolizer
deal with elseFilter, some cleanup
Add a separate test case for write
do not hard-code the namespaceURIs multiple times