Fix colorgroup_colorlist.html: url argument is slug, not color_hex
Move colorgroup_list to class based view ColorGroupListView
Remove obsolute colorgroup_list view and template
Removed unused add_message function in DWStyles.views
Fix colorbar.html using color_hex argument in url call instead of slug
Move S2LayerParse to its own code file
Make sure S2LayerParse catches multiple objects returned for theme searches