add Raster to the list of SYMBOLIZER_PREFIXES, p=ahocevar, r=me (closes #2642)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@10350 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Style.js

@@ -438,4 +438,5 @@ OpenLayers.Style.createLiteral = function(value, context, feature, property) {
  * {Array} prefixes of the sld symbolizers. These are the
  * same as the main geometry types
  */
-OpenLayers.Style.SYMBOLIZER_PREFIXES = ['Point', 'Line', 'Polygon', 'Text'];
+OpenLayers.Style.SYMBOLIZER_PREFIXES = ['Point', 'Line', 'Polygon', 'Text',
+    'Raster'];