check that visual studio's tools returned the env to set
allow building outside of the uu.micros directory

- use windows bash path
- make sure the paths we set in environment are absolute
allow uu.micros to be used as a git submodule

modularize build script: allow files outside this repository

--src-dir allow to add new source dirs to the build
--output-dir allow to set the destination dir
let us use uu.micros as a submodule

* f-playground-as-submodule:
  allow uu.micros to be used as a git submodule
  allow building outside of the uu.micros directory
  check that visual studio's tools returned the env to set
put name of gl version in the rendering function

this helps communicating with which opengl version we are dealing with