Upgrade to latest Rust
Merge pull request #252 from bvssvni/master

Upgrade to latest Rust
Upgraded to latest Rust
Merge pull request #253 from bvssvni/master

Upgraded to latest Rust
Removed outdated '.rlib' information

Closes https://github.com/PistonDevelopers/piston/issues/254
Fixed word order
Changed path method on AssetStore to take &self insted of &mut self
Merge pull request #258 from leonkunert/master

Changed `path` method on `AssetStore` to take `&self` insted of `&mut self`.
Removeds chapter `loading sounds` from tutorial

Closes #247
Merge pull request #259 from leonkunert/master

Removeds chapter `loading sounds` from tutorial
Add a preliminary AudioBackEnd which is able to play sound
Rewrote `Game` trait to use iterator

Closes https://github.com/PistonDevelopers/piston/issues/260
Merge pull request #261 from bvssvni/master

Rewrote `Game` trait to use iterator
Using `Args` types in `Game` trait

Closes https://github.com/PistonDevelopers/piston/issues/262
Merge pull request #263 from bvssvni/master

Using `Args` types in `Game` trait
Removed `AssetStore` from `Game` methods except `load`

Closes https://github.com/PistonDevelopers/piston/issues/264
Merge pull request #265 from bvssvni/master

Removed `AssetStore` from `Game` methods except `load`
Removed unused methods on `Game` trait

Closes https://github.com/PistonDevelopers/piston/issues/266
Merge pull request #267 from bvssvni/master

Removed unused methods on `Game` trait
Updated example

Closes https://github.com/PistonDevelopers/piston/issues/255