Added joystick input

Added position as out variable from vertex shader.

Adding the position out form vertex shader makes us skip computation of position in the fragment shader based on gl_FragCoord.

Add No-Brain Jogging to examples

standardized glsl variable naming

implemented custom fragment shader support

add a guide for making scenes

fix typo for matrix

CI support for example/amidakuji

Adds video mode support and a community example for its usage.

readme: remove tracking from Gitter URL