Add create() and getLocalFunctions() to function registry so it can be used for plugins

Author: matthew-dean

lib/less/functions/function-registry.js

@@ -20,8 +20,14 @@ function makeRegistry( base ) {
         get: function(name) {
             return this._data[name] || ( base && base.get( name ));
         },
-        inherit : function() {
+        getLocalFunctions: function() {
+            return this._data;
+        },
+        inherit: function() {
             return makeRegistry( this );
+        },
+        create: function(base) {
+            return makeRegistry(base);
         }
     };
 }