Add more sample name options

[troycomi]

• Added an argument to get_samplename_list so samples can be matched
  with population, superpopulation or sample.
• Added options to specify modern super population and archaic sample
• Changed logic of parser so none of those are required. Instead,
  check if either list is empty and raise an exception if so indicating
  which options should be specified.

[lparsons]

Thanks for the addition, it looks good to me!

Before we merge, could we add a note to the changelog and bump the version number?

[troycomi]

Will add in the next push. It will be a few days before the empirical data is run through.