Some renaming & cleaning up

	modified:   Makefile
	renamed:    free_fermi_proj.f90 -> free_fermi.f90
	modified:   free_fermi_gc.f90
	renamed:    free_fermi.f90 -> free_fermi_recurse.f90
Move recursion relation method to altsrc directory
Minor changes; checked for d=2,4

  - Code seems to work for arbitrary dimensions. I checked the two
    versions (recursion relation and particle number projection) and
    they agree for d=2,3,4. They should agree for other values of d
    too. The methods are completely different so this is a good test.

  - Make the grand-canonical code a bit more general
Update README.md
Clean up main program a bit