Writing more in-depth pseudocode for implementing the function.
Finished a ROUGH `source_tablematch_counter` that works w/ default kwargs.

Tested. But needs heavy code refactoring / prettying / documenting.

Good thing it's short.
Upgraded source_tablematch_counter - should be done, is pretty, etc.
Wrote `table_tablematch_counter()`, tested it.

Realized that I'd already computed all those numbers by hand...
Added Stassun 1999; didn't add it to the tables list.

only a single star matched between ONCvars and Stassun, so it's been abandoned.
Created base spec for period_digger, with five internal functions
Wrote docstring/detailed spec for GCVS_period_get().
Finished writing GCVS_period_get(); tested it.
Wrote and tested `CHS01_period_get()`. It works!
Fixing overlooked wrongtext in docstring - it got copied without updating.
Wrote and tested `YSOVAR_period_get()`. It works!
Wrote `Herbst_period_get()` and tested it! it works great.
Finished `Parihar_period_get()`: it works! Tested.