bring back template option (close #832)

Author: yyx990803

lib/template-compiler/preprocessor.js

@@ -15,6 +15,11 @@ module.exports = function (content) {
     ))
   }
 
+  // allow passing options to the template preprocessor via `template` option
+  if (this.options.__vueOptions__) {
+    Object.assign(opt, this.options.__vueOptions__.template)
+  }
+
   // for relative includes
   opt.filename = this.resourcePath