SFTP don't support AES-CTR

One of my servers had sshd configured to accept only AES-CTR keys (aes256-ctr,aes192-ctr,aes128-ctr).
Textastic was unable to connect to it, and the log wasn't helpful.

Since I already encountered this issue in the past, I modified the configuration of that server to accept also AES-CBC (aes256-cbc,aes192-cbc,aes128-cbc) and the sftp connection now works well.

Unfortunately, this means that Textastics ssh subsystem doesn't support AES-CBC.