Removed some unnecessary references to PyCrypto's Crypto.Hash functions in the ECDSA code since it uses hashlib functions anyways. This removes an ECDSA dependency on PyCrypto.
Fixed tests so that they will still run without failure when
dependencies (PyCrypto, ecdsa) are missing. (Tests are skipped if
libraries are not present.)
Added reference to unittest2 so that Python 2.6 can use skipIf
Merge pull request #50 from mark-adams/fix_tests_when_deps_missing

Fixed tests so that they will still run without failure when dependencies (PyCrypto, ecdsa) are missing
Modified RSA algorithms to use cryptography library instead of PyCrypto
Modified ECDSA algorithms to use cryptography library instead of ecdsa.
Added some missing ensure_bytes in a couple of the tests.
Consolidated testing variables for has_rsa and has_ecdsa into has_crypto.
Updated README and dependencies in tox.ini
Added name to AUTHORS
Incremented version to 0.4
Merge pull request #51 from mark-adams/change-to-cryptography

Switch to cryptography for RSA and ECDSA algorithms