Merge pull request #301 from reem/contributing-guide

Copied contribution guide to CONTRIBUTING.md
Added admins

Closes https://github.com/PistonDevelopers/piston/issues/302
Updated contributing link

Closes https://github.com/PistonDevelopers/piston/issues/303
Replaced `#[deny(dead_code)]` with `#[warn(dead_code)]`

Closes #312
Merge pull request #313 from leonkunert/master

Replaced `#[deny(dead_code)]` with `#[warn(dead_code)]`
Fixed compiler errors

Closes https://github.com/PistonDevelopers/piston/issues/308
Closes https://github.com/PistonDevelopers/piston/issues/309
Closes https://github.com/PistonDevelopers/piston/issues/310
Merge pull request #314 from bvssvni/master

Fixed compiler errors
Fixed code in `gl_back_end`

Closes https://github.com/PistonDevelopers/piston/issues/311
Closes https://github.com/PistonDevelopers/piston/issues/315
Merge pull request #316 from bvssvni/master

Fixed code in `gl_back_end`
Upgrade to latest Rust-Empty
Merge pull request #328 from bvssvni/master

Upgrade to latest Rust-Empty
Added link to issue

Closes https://github.com/PistonDevelopers/piston/issues/329
Passing `Args` as pointers to `Game` trait methods

Closes https://github.com/PistonDevelopers/piston/issues/325

This will break everything.
Merge pull request #333 from bvssvni/master

Passing `Args` as pointers to `Game` trait methods
Added `event` method on `Game` trait

Closes https://github.com/PistonDevelopers/piston/issues/332
Merge pull request #334 from bvssvni/master

Added `event` method on `Game` trait
Upgraded to latest gl-rs
Merge pull request #336 from Coeuvre/master

Upgraded to latest gl-rs
Upgraded to latest Rust-Empty
Merge pull request #337 from bvssvni/master

Upgraded to latest Rust-Empty