performance improvements

store parsed category description
removed mongo _key from returns
dont get category teaser for parent

src/database/mongo/helpers.js

@@ -6,6 +6,7 @@ helpers.toMap = function(data) {
 	var map = {};
 	for (var i = 0; i<data.length; ++i) {
 		map[data[i]._key] = data[i];
+		data[i]._key = undefined;
 	}
 	return map;
 };