handle unwrapped exceptions in the general exceptions handler
handle unwrapped exceptions in the general exceptions handler

python 2 was ok with None, BaseException descendents, and tuples of those in `except` clauses. Python 3 doesn't allow None, or tuples of None. This change moves handling this case into the general Exception block and checks before it wraps the exception

lucaswiman/parsimonious,erikrose/parsimonious