Add support for PKCS #1 v1.5 RSA encryption

Like it or not, needed for compatability with a lot of existing
protocols. The default for encrypt/decrypt remains OAEP of course.
Add support for RSA signing with alternate hashes (MD5, SHA-512, etc)
Update readme with new hash/padding options
Add support for HMAC, RC4, AES-128, hex encoding, etc
Add RC4 and AES-128 support to Cryptor
Take hash test inputs as hex strings. Add MD5 tests.
Add CTR and GCM support
Remove GCM support for now, EVP is more complicated than that
Update for Rust 0.6

Also disable AES_128_CTR and AES_256_CTR because they cause link
failures on OS X.
Remove debug prints in Crypter::final()
Tweak for rust trunk (c081ffb 2013-04-30 02:21:37 -0700)
Remove unnecessary `unsafe` blocks
Update for current incoming
Update for latest incoming (3a3bf8b)
Update to latest incoming (878a9b9)
Don't error on `make clean` if there is no dylib
Update for latest incoming (4a52ff0)
Remove unused use warning on latest incoming (eac0200)
Update for 0.7
Update for 0.8-pre (f503e53)