initial copy of ZODB3-3.9.7's ZODB/scripts/analyze.py.
define main() so that it can be scriptified by zc.recipe.egg.
use ZODB.utils.get_pickle_metadata instead of pickle.Unpickler.

* it is faster.
* it does not require Products.
sort output by total size.
display current/old information for each class.
support csv output by '-c' or '--csv'.
remove unused variable.
support using DBM as temporary storage to limit memory usage by '-d' or '--dbm'.
add README.zodbanalyze.txt.