Named arguments to call should stay named arguments when called

Author: xzyfer

src/bind.cpp

@@ -107,7 +107,7 @@ namespace Sass {
             (*arglist) << SASS_MEMORY_NEW(ctx.mem, Argument,
                                           key->pstate(),
                                           argmap->at(key),
-                                          name,
+                                          "$" + name,
                                           false,
                                           false);
           }

src/functions.cpp

@@ -1589,7 +1589,7 @@ namespace Sass {
           *args << SASS_MEMORY_NEW(ctx.mem, Argument,
                                    pstate,
                                    expr,
-                                   "",
+                                   arg ? arg->name() : "",
                                    arg ? arg->is_rest_argument() : false,
                                    arg ? arg->is_keyword_argument() : false);
         } else {