Beef up t_vertex.c:

Beef up t_vertex.c:
	- cope with input vectors with size less than that of the emitted
	  attribute.
	- cope with vertices with 'holes' inside and between vertices.

Fix calculation of tnl->render_inputs to work with fp programs.
Mirror VB->PointSizePtr in VB->AttribPtr so that it can work with t_vertex.c.

Transition swrast_setup/ to use t_vertex.c to build swrast vertices.