vertex arrays renamed to varray_ and exposed to rest of engine

vertex arrays renamed to varray_ and exposed to rest of engine
mesh_maxtris and mesh_maxverts exposed (really only intended for R_Mesh_ResizeCheck #define)
R_Mesh_GetBuffer is gone, R_Mesh_State takes it's place for most of it's functionality
R_Mesh_ResizeCheck (a #define) will expand arrays on the fly if a mesh is too big (note: be sure to use this if you have a mesh that may be more than 1024 triangles, 3072 verts)
R_Mesh_Draw takes the place of R_Mesh_Render and takes two parameters (number of verts and number of triangles)
fixed bug that caused sky to appear through models when sky was onscreen (R_DrawWorld must be called at a specific point in rendering, had forgotten that)

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@2337 d7cf8633-e32d-0410-b094-e92efae38249