Return values
The function returns the major and minor version numbers and the revision for the currently used
OpenGL™ implementation as a list (major minor rev).

Description
The function returns the OpenGL™ implementation version. This is a convenient function that parses
the version number information from the string returned by calling
glGetString( GL_VERSION ). The OpenGL™ version information can be used to determine
what functionality is supported by the used OpenGL™ implementation.

Notes
An OpenGL™ context must be created before this function can be called (i.e. an OpenGL™ window
must have been opened with glfwOpenWindow).