[BLEUNW/GUI/RENDERABLE]: added a 'renderable' class for the gui::manager.
[YAGGLER/DATA/SHADERS/TEST]: some test shaders (mostly fake volumetric-like raymarchers)
[BLEUNW/SAMPLE/GUI/TEST]: a sample to test the bleunw's GUI
[YAGGLER/CMAKE]: commented unused samples, added the gui-test sample.
[KLMB/SHADER-FRAMEWORK/DEFAULT-SHADER]: default shader are now using the k:lmb framework.
[BLEUNW/GUI/TEXT]: text now have an uniform to set its base color. (uniform font_color: vec4)
[KLMB/COMPOSITOR/PASS]: the fsquad vertex fragment is now shared across all passes of the prog.
[KLMB/MATERIAL/USINGS]: added the shared_* for shader's shared_instance.
[KLMB/OBJECT]: rendering now use a scoped 'use()' for the vao.
[KLMB/COMPOSITOR/DATA/SHADER/FSQUAD]: the vertex shader now use the std .vert format for outputs (as expressed in the klmb default shaders)