* added spirograph program
* add graphics forlder to cmake
* updating DIRECTORY.md
* enable VNC for GUI programs on gitpod
* fix cpplint error
* fix macro definitions for correct documentation
* fix filename in docs
* move include from namespace to global
* download and build freeglut if not available
* install opengl libraries for build check
* fix syntax error
* fix quotes
* install mesa-utils instead
* use markepplace tool instead of installing
* fix syntax
* undo changes to github actions
* OpenGL not mandatory
* add private option to compile definition
* fix: corrected to compile definitions instead of options
* use the macro USE_GLUT
* compile FREEGLUT as a subdirectory. this maintains a consistency
* build freeglut_static when GLUT library not available
* provide keyboard control
* clang-tidy fixes for cb284bddb2
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