[Maxima] Rearranging lbfgs code

[Raymond Toy]

Since I need to run f2cl over the existing Fortran code, I'd like to
rearrange the lbfgs code.  Basically, I just need to move each of the
functions in lbfgs.f into it's own file so that we can compile them in
the right order.   This gets around the issue that Robert had to
manually reorder the lbfgs.lisp file to get rid of some warnings and
such. 

I think it's best that we touch the generated lisp files as little as
possible.

For simplicity, I probably won't add a defsystem since lbfgs wasn't
using a defsystem previously.

Ray