API docs for propka

- use autosummary (with custom module template)
- updated module docs for all modules so that they are included
  with sphinx autodocs

propka/iterative.py

@@ -1,6 +1,10 @@
-"""Iterative functions for pKa calculations.
+"""
+Working with Determinants
+=========================
+
+Iterative functions for pKa calculations. These appear to mostly
+involve :class:`propka.determinant.Determinant` instances.
 
-These appear to mostly involve determinants.
 """
 from propka.determinant import Determinant
 from propka.lib import info, debug