Readme

Signed-off-by: Khral Steelforge <garuda2550@gmail.com>
readme, how to compile.

Signed-off-by: Khral Steelforge <garuda2550@gmail.com>
NULL to nullptr.

Signed-off-by: Khral Steelforge <garuda2550@gmail.com>
Merge branch 'master' into opengl