Using 3D camera from Piston

Closes https://github.com/PistonDevelopers/hematite/issues/67
Merge pull request #68 from bvssvni/cam

Using 3D camera library from Piston
Updated Cargo.lock
Merge pull request #71 from bvssvni/master

Updated Cargo.lock
Port to gfx-rs
Merge pull request #70 from cmr/gfx

Port to gfx-rs
fps_counter: rolling frame counter for accurate FPS.
Remove any FPS caps to allow accurate comparisons.
Move buffer building out of the event loop.
Merge pull request #74 from eddyb/fps-counter

FPS counter.
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
Use vecmath library from Piston