Fix wrongly-named formal parameters in three places: begin_y was used twice instead of begin_y and begin_x for derwin(), subpad(), and subwin(). Reported for derwin() by Eric Huss.
Fix wrongly-named formal parameters in three places: begin_y was used twice
instead of begin_y and begin_x for derwin(), subpad(), and subwin().
Reported for derwin() by Eric Huss.

Added class annotations for the window methods so they would be properly
described in the index.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator