* Update dependencies
- Closes#270
* Unify controls in Invaders example
The fire button on gamepads was allowing trapid fire when holding the
button. Keyboard controls required the fire key to be released between
each shot fired. This commit fixes the difference by making the gamepad
fire button act like the keyboard fire key.
* Move all examples to individual crates
* CI: Add libsdl2
* Use Ubuntu bionic for updated libsdl; 2.0.8
* Clippy
* libudev-dev is a dependency of libsdl2-dev
* Clippy
* Remove unnecessary dev-dependency
* `winit` is actually used in unit tests
* Fix a typo
* Move `simple-invaders` crate
