Merge pull request #25 from CartoDB/allow_expression_in_polygon_pattern_file

Added expression property to `polygon-pattern-file` and `line-pattern-file`

lib/carto/torque-reference.js

@@ -1047,7 +1047,8 @@ var _mapnik_reference_latest = {
                 "type": "uri",
                 "default-value": "none",
                 "required": true,
-                "doc": "An image file to be repeated and warped along a line"
+                "doc": "An image file to be repeated and warped along a line",
+                "expression": true
             },
             "clip": {
                 "css": "line-pattern-clip",
@@ -1127,7 +1128,8 @@ var _mapnik_reference_latest = {
                 "type": "uri",
                 "default-value": "none",
                 "required": true,
-                "doc": "Image to use as a repeated pattern fill within a polygon"
+                "doc": "Image to use as a repeated pattern fill within a polygon",
+                "expression": true
             },
             "alignment": {
                 "css": "polygon-pattern-alignment",