Having a hook to compile templates while using the new plugin API seems to be very difficult ATM. Would be useful to have some way to add/remove scripts before they touch plugins like commonjs. Maybe something like:

build.each('templates', function (file, conf) {
  conf.remove('templates', file);
  file.contents = jade(file.contents);
  file.filename = 'template.js';
  conf.add('scripts', file);
});

Would you accept a PR?