Update generator to support underscores in template filename extensions.

This is to support cases such as Go where the compiler looks for all .go
files in the directory and reports functions and variables as redeclared
because they exist in both the template and generated file.

lib/generator.js

@@ -20,7 +20,9 @@ Generator.getTemplatesSync = function () {
 
 Generator.parsePath = function (fullpath) {
   var dir = p.dirname(fullpath);
-  var output = p.basename(fullpath).replace('.tmpl', '');
+  var output = p.basename(fullpath).replace('.tmpl', '').replace(/(_)/g, function (match, _, offset, string) {
+    return offset > string.lastIndexOf('.') ? '' : '_';
+  });
   return {
     fullpath: fullpath,
     fullOutputPath: p.resolve(dir, output),