Add a bunch of missing python docstrings.

This appeases pylint, so un-disable its docstring warning.

redo/atoi.py

@@ -1,5 +1,7 @@
+"""Simple integer conversion helper."""
 
 def atoi(v):
+    """Convert v to an integer, or return 0 on error, like C's atoi()."""
     try:
         return int(v or 0)
     except ValueError: