added keygen decorator to generate key, validate against signature, call func;
added _keygen, validate, isvalid, signature, and other functions in '_inspect';
added test_ignore to test 'ignoring' of argument names and indicies;
added test_validate to test validate's ability to raise the correct error 


git-svn-id: svn+ssh://svn.mystic.cacr.caltech.edu/pathos/klepto@563 8bfda07e-5b16-0410-ab1d-fd04ec2748df
Merge branch 'master' of https://github.com/uqfoundation/klepto