several improvements

I've done several improvements here, including:

- @camspiers traits support
  * leave traits implemented as classes, to prevent problems requiring or referencing them.
- update version of PHP-Parser, which now supports binary numbers https://github.com/igorw/galapagos/issues/5
- convert function calls with different signature
  * `stream_context_create`
  * `session_set_save_handler`
- improve `ObjectInstAccess` to support function calls
- fix `isset` calls when used with object/array instant access 
  * `isset((new stdObject)->hello)` => `($tmp = new stdObject) ? isset($tmp->hello) : isset($tmp->hello)`
@igorw actually it should be yours, I left mine here just for testing.

if you don't mind I could help you with maintenance of this project!