renamed klepto.archives.archive_dict to klepto.archives.cache;
test_basic uses assert, does basic sanity check;
klepto.safe caches are more safe, as TypeErrors are caught from unhashable keys;
added dict_archive, which is basically a dict with the archive interface


git-svn-id: svn+ssh://svn.mystic.cacr.caltech.edu/pathos/klepto@555 8bfda07e-5b16-0410-ab1d-fd04ec2748df
Merge branch 'master' of https://github.com/uqfoundation/klepto