`load()` a template and then `interpolate()` it with data.  ### Example  this.get('#/', function() { this.render('mytemplate.template', {name: 'test'}); });
function(location, data, callback) {
      if (_isFunction(location) && !data) {
        return this.then(location);
      } else {
        if (!data && this.content) { data = this.content; }
        return this.load(location)
                   .interpolate(data, location)
                   .then(callback);
      }
    }