Monochromatic.wavelength option not prompting.

[AustenWallis]

Upon selecting a monochromatic spectrum option for the Central_object.rad_type_in_final_spectrum(bb,models,uniform,mono) (bb) :mono
and the
Disk.rad_type_in_final_spectrum(bb,models,uniform,mono,mod_bb) (bb) :mono
, the user is not prompted for the specific wavelength desired with the monochromatic.wavelength parameter.
my_new_model14.pf.txt

The documentation for this option will need to be updated upon solving of this issue.

[jhmatthews]

This is due to a mismatch between num_choices, which is hardwired in two places (in get_choices and init_choices). It was changed in one place (init_choices) without the other. Ideally there should be a link between them, so I'll fix that .

[jhmatthews]

Proposed fix #1094 -- can confirm this does make Austen's model prompt correctly for specific wavelength.