Update to latest piston and gfx-rs
Use X to turn on/off extrapolation
Use Z to toggle update camera on render
Fixed bug in extrapolated time
Fixed indention + use 60 FPS
Upgraded to latest Piston
Removed X/Z
Minor fixes

* Removed unneeded trailing comma
* Removed unused `Update`
Merge pull request #75 from bvssvni/master

Update to latest piston and gfx-rs