Single precision update

[abelsiqueira]

Tried updating #177, but there are some errors. Maybe ELFUN.f and similar are not multipre precision?

[dpo]

I was working on this too and I observe segfaults. ELFUN, etc., are always double precision. I have to try and write a single precision Fortran driver to see if that works.

[abelsiqueira]

Sorry, forgot to say I had segfaults too. The simplest segfault was something like

nlp = CUTEstModel("ROSENBR")
io_err = Cint[0]
nvar = 2
x = Cfloat[-1.2; 1.0]
f = Cfloat[0]
ccall(dlsym(CUTEst.cutest_lib_single, :cutest_ufn_), Nothing,
      (Ptr{Int32}, Ref{Int32}, Ptr{Cfloat}, Ptr{Cfloat}),
      io_err, nvar, x, f)

[dpo]

Same here. Decoding the problem with --single has no effect. I don't think the problem is in the Julia interface.

[amontoison]

@abelsiqueira I merged your modifications in #371