out into r_graph.c (Time and Z graph), cl_ngraph.c (Net graph), and
{gl,sw}_graph.c (R_LineGraph). gl_ngraph.c is gone. Unfortunatly, something
is rather wrong with NetGraph in gl (probably R_LineGraph).
glquake.h to mathlib.h (along with the declaration for frustum) and the
extern inline keyworws protected by an ifndef so that mathlib.c can cause
R_CullBox to be compiled publicly. The definition of frustrum has been moved
from its verious locations into mathlib.c.
