Merge pull request #18 from bvssvni/master

Upgraded to latest Rust
Update events.dt when setting a new update interval.

Fixes #20
Merge pull request #21 from featureenvy/ups-dt-fix

Update events.dt when setting a new update interval.
Point "time" to crates.io

Closes https://github.com/PistonDevelopers/event_loop/issues/22