Updated to close session if we get a CKR_DEVICE_REMOVED on logout

Win32-specific PKCS#11 definitions created

Updated to retrieve function pointers using lookups rather than
C_GetFunctionList on Win32 since ActivClient doesn't seem to return
valid function pointers...

Updated to return fake PKCS#11 error "MAYBE_LOGIN" if we are unable to find
any private key objects

Updated to try C_Encrypt for encryption before trying C_Sign.

Updated to unpad (PKCS 1.5 mode 1 only) input when encrypting since some
drivers require the input to be unpadded

Minor cleanup

Updated test driver to support logging in if MAYBE_LOGIN is recieved