Update to FParser 4.5.1

Starting this PR to discuss the update from fparser 4.5 to 4.5.1.

The two first commits update to the distributed files from upstream and check in the generated files (for fpoptimizer).

This does not contain @roystgnr's NaN stuff yet. Is that in the libmesh/fparser_nan branch? Then I could cherry pick (or hand port if necessary).

It builds with the existing makefiles (from libmesh), but is not thoroughly tested.