[YAGGLER/CXX-SETUP]: set or'able values to setup enums
[YAGGLER/MAIN_HEADER]: a bit clearer comment when yaggler/setup is not included
[YAGGLER/EXCEPT]: do not print the message when YAGGLER_NO_MESSAGES is defined and when the context is not a debug context
[YAGGLER/GLFW-WINDOW]: more readable constructor