This commit splits up handling of the crypto stream and the other streams in the framer, crypto setup, and the packer.
- Crypto stream data is handled separately and should never be sent unencrypted or FW-secure. Fixes#544.
- Non-crypto stream data is only sent with FW encryption on the server and only with non-FW or FW encryption on the client. Fixes#611.
The crypto stream is current excluded from flow control (#657), but that shouldn't be an issue in practice for now.