changes to Crypt_Random

'cause I don't think the Crypt_* objects ought to be required.

Like with Net/SSH2.php RSA is implemented internally within it for the server signature verification. Crypt/RSA.php isn't used for that and as such if you're not doing RSA key auth than you could, in theory, do away with ~100kb of bloat and just exclude Crypt/RSA.php all together. For RSA key auth that bloat is needed because most of that bloat is for dealing with all the various different key formats (the rest deals with PSS or OAEP padding, neither of which SSH2 uses, but that's trivial compared to the key handling bloat).

With RC4.php there's some bloat as well. You don't need pbkdf1 or pbkdf2 that Crypt/Base.php implements. The mcrypt handling portion is largely going to be unnecessary as well.