Version 0.0.3-beta

Moved config interface to main tabs.
Gave the notification an icon, so it's easier to see.
Added an interface for importing your own keys and certificates (using .pem and .p12 files) to verify the server or authenticate yourself to a server. (see the CAfile and cert options in stunnel)

Edit: Just realised I forgot to bump the version number in gradle, so you should use version 0.0.4-beta instead.