ProtogenSSH: Passwords are not stored in encrypted SharedPrefs

[JaredTamana]

Due to some issues with the crypto classes, passwords are currently stored alongside username and port info in regular SharedPrefs. This should probably be corrected. When I close this issue, I'll likely maintain a version of ProtogenSSH that does not use the crypto, as the current SDK I'm building for does not support it, but I want people to be able to use old phones they have knocking around if they choose to do so.