The Piston core is now 0.5 and includes some breaking changes:
eventcrate is merged with the
event_loopis reexported as a module under
If you are using Piston-Window these changes will not have much effects.
To fix your code, replace
use piston::event::*; with
The motivation for this change is to make it easier to maintain generic libraries
by depending on
In many cases you do not need a window abstraction to share code between projects.
Such libraries include controllers, AI and UI.