Change Marko Implementation to support v4

Marko changed its implementation and thus "The render callback will no longer receive a string in Marko v4. Use `renderToString(data, callback)` instead" See marko-js/marko#450.

This change is compatible with the current stable public version.

Author: eikaramba

lib/consolidate.js

@@ -1452,7 +1452,7 @@ exports.marko = function(path, options, fn){
 
     try {
       var tmpl = cache(options) || cache(options, engine.load(path, options));
-      tmpl.render(options, fn)
+      tmpl.renderToString(options, fn)
     } catch (err) {
       fn(err);
     }
@@ -1470,7 +1470,7 @@ exports.marko.render = function(str, options, fn) {
 
     try {
       var tmpl = cache(options) || cache(options, engine.load('string.marko', str, options));
-      tmpl.render(options, fn)
+      tmpl.renderToString(options, fn)
     } catch (err) {
       fn(err);
     }