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).

It builds with the existing makefiles (from libmesh), but is not thoroughly tested.

This contains:
* The treadsafe eval patches
* The NaN stuff form libmesh/fparser_nan