Merge from vendor branch TNF:

Merge from vendor branch TNF:
Import tex-pxfonts-2010 as fonts/tex-pxfonts.

Pxfonts supplies virtual text roman fonts using Adobe Palatino (or
URWPalladioL) with some modified and additional text symbols in the OT1,
T1, and TS1 encodings; maths alphabets using Palatino/Palladio; maths
fonts providing all the symbols of the Computer Modern and AMS fonts,
including all the Greek capital letters from CMR; and additional maths
fonts of various other symbols. The set is complemented by a sans-serif
set of text fonts, based on Helvetica/NimbusSanL, and a monospace set
derived from the parallel TX font set. All the fonts are in Type 1
format (AFM and PFB files), and are supported by TeX metrics (VF and TFM
files) and macros for use with LaTeX.