Replace IntrinsicFunctions.f with version sent by Tom LeFebvre on 22 Feb 2013.  A quick comparison suggests the only difference between the two files are the end-of-line characters, but a rigorous line-by-line check was not done.
Replace ExtFtn.h with version sent by Tom LeFebvre on 22 Feb 2013.  There is no difference between this file and the previous version but now we know the provenance of the file and the license conditions, which is public domain.
Move ExtFtn.h into src.

The previous ExtFtn.h was in the wrong place.  The contents of the file
has not changed.
Merge pull request #8 from jwblin/master

Replace the final two files from Tom LeFebvre, ExtFtn.h and IntrinsicFunctions.f