Added failing test for #11
added global_service.reset(). call this on a global service instance to force a refresh

This provides a workaround for #11:
* Make sure the service you are using is global ( `service = syncify f,
global: yes` )
* Whenever you want ot force an evaluation call service.reset. Any
blocks using `syncify.busy service` should work just fine
0.3.2