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
put name of gl version in the rendering function

this helps communicating with which opengl version we are dealing with