Add truly random numbers and use them in places where randomness matters
Use a new, truly random secret for cookie encryption
Add AES from phpseclib and use it for cookie encryption

This replaces the deprecated and broken Blowfish implementation that has
previously been used and should provide a lot more security.
auth_random: remove exception comment as there is no exception
auth_en/decrypt: Add explanation and more efficient decryption

Added an explanation that what we do is like normal CBC but that we
additionally encrypt the IV which is actually suggested by the NIST for
non-random (but unique) IVs. In the decryption process it's not
necessary to decrypt the IV, this should save some time.
Merge pull request #242 from splitbrain/aes_prng

Add AES encryption and better random numbers FS#2685