graphics/ptex: create port

Ptex is a per-face texture mapping system developed
by Walt Disney Animation Studios.

Ptex applies a separate texture to each face of a polygon mesh.
It's file format can efficiently store hundreds of thousands
of texture images in a single file.

WWW: http://ptex.us

PR: 222300
Submitted by: Shane <FreeBSD@ShaneWare.Biz>