some minor changes on sl_function macro

 - moved helper function to call annotated scala function from Application into a Trait in sl_function.scala
 - this function now checks if the called function ends with helper_function_postfix
 - added new config helper_function_postfix this is the postfix of the helper function generated by the sl_function macro
bugfix in module translators

the returned sl type was not correct eg Opt.Option ( Int ) changed to ( Opt.Option Int )
new translators for either and tuple2

they seem to work. no unit test are written yet