added full screen support

added full screen support
added swap_buffers method
fixed title error
added resize_callback

added resize_callback
added test project folder to .gitignore
fixed callback error

fixed callback error
fixed background error
added WIN32_LEAN_AND_MEAN macro to definitions.h
added width and height fields in gl_window

added width and height to gl_window
added fullScreen to gl_window
added private set_size function in gl_window
ChangeDisplaySettings is only called if fullScreen is true
added keys enum (empty)