Reorganize a bit
Update reference data; add test script; update run scripts
Bugfix in free_fermi.f90

  - Introduced bug recently while cleaning things up in zlog1p. Undo!
  - Same for calc_nmu!
  - Tested carefully: this version works.
Automate test for free_fermi.f90
Automate test for recursion relation version; bump version number in free_fermi.f90
Some comments, cleanups in free_fermi.f90
Include spin degeneracy as a parameter in recursive code
Bump version in free_fermi.f90
Update .gitignore