Rename "roles" to "units". Put units in their own folders.

lib/units/storage/plugins/image/param/crop.js

@@ -0,0 +1,14 @@
+var RE_CROP = /^([0-9]*)x([0-9]*)$/
+
+module.exports = function(raw) {
+  var parsed
+
+  if (raw && (parsed = RE_CROP.exec(raw))) {
+    return {
+      width: +parsed[1] || 0
+    , height: +parsed[2] || 0
+    }
+  }
+
+  return null
+}