added 'ignore' keyword to caches; _keygen can now ignore 'self' for methods
change how keys are built (varargs, argskwds) for cache and keygen;
updated test_cache and test_ignore for new-style keys


git-svn-id: svn+ssh://svn.mystic.cacr.caltech.edu/pathos/klepto@565 8bfda07e-5b16-0410-ab1d-fd04ec2748df
Merge branch 'master' of https://github.com/uqfoundation/klepto