Deprecating simcoal and fdisk content in PopGen

Dear all,

I would like to deprecate a big part of PopGen, that is:
- All the simcoal stuff
- All the fdist stuff.

Simcoal comes from the lack of source code and a free license.
fdist from a lack of license.

In simcoal case, I do not think we should support black box code (unless 
it is something very very popular which is definitely not the case).

For the fdist case I suspect that 99%+ of the users are via my own 
applications, and I will take care of that myself. We would benefit my 
reducing Biopython's complexity a little bit.

For simcoal, I understand that there might be a few (handful at most?) 
users, but I think the trade-off is well worth it.

Any opinions?

Regards,
Tiago