do not fmod() on the lighting calculcations

This is what caused faces to occasionally go black when exactly facing the light
make a camera transform matrix without any translation for skybox rendering
add shader based opengl skybox rendering and remove obsolete opengl cruft
support 8 bit indexed, RGB, and RGBA png images allow png load to flip vertically and horizontally flip skybox textures horizontally so not mirrored on the inside of the cube map
filled wireframe opengl drawing
Change license of the wireframe shaders to gplv2

with permission of the author, Alexandros Frantzis,

	Hi Jeremy,

	thanks for letting me know. Feel free to use the shader with GPLv2.

	Thanks,
	Alexandros