Unused variable
PEP-8 line spacing
Fix non-idiomatic comparison with None
Add shortnames arg to typestats()

This also changes typestats to return a defaultdict, which drops Python
2.4 support.  I'm not sure how I feel about this.  Actually I'm more
bothered by the repr() changing.

TODO: see if pprint can deal with defaultdicts sanely.
Add back Python 2.4 compatibility

Besides, pprint.pprint() doesn't know how to pretty-print defaultdicts.
Add shortnames arg to most_common_types()
Add shortnames arg to show_most_common_types
Add shortnames arg to show_growth
count() accepts fully-qualified type names
by_type() accepts fully-qualified type names
Add shortnames arg to all graphing functions
Update changelog
Update function signatures in the documentation