Got Lightmapping working

The surfaces in the BSP maps are now lightmapped (lightmaps are
information stored in the map file about how bright each part of a
surface is).
Objectified OpenGL light and material code

Light and Material classes now serve as containers for opengl lighting
information.
GLFunctions (.cpp/.h) is where opengl extension functions (i.e., ones
that were added after opengl 1.1) are defined and loaded.
Math (.cpp/.h) is where we'll keep common structures that involve math
(e.g., geometric vectors).
The Console will be a property of the engine where other parts of the
engine can produce text output, and eventually where the user can issue
certain commands.