Update to Handlebars v4.0 and disable implicit partial indenting because it is incredibly counter-intuitive

Author: taylorhughes

lib/loader/scriptresource.js

@@ -284,7 +284,11 @@ HandlebarsResource.prototype.buildFunctionString_ = function() {
 
   var template;
   try {
-    template = Handlebars.precompile(source);
+    // TODO(Taylor): Allow other options to be passed in somehow.
+    template = Handlebars.precompile(source, {
+      preventIndent: true
+    });
+
   } catch (e) {
     e.fileName = this.filePath;
     var lineNumberMatch = (e+'').match(/Parse error on line (\d+)/);