FIX: password support is added

It is quite natural to provide a password (or passphrase)
to establish a FIX session i.e. in a logon request. If a
particular exchange requires password to be provided we
have to support this

Signed-off-by: Marat Stanichenko <mstanichenko@gmail.com>
Signed-off-by: Pekka Enberg <penberg@iki.fi>