New Encryption Plugin API
- Use extension points instead of Events to decrypt/encrypt. That way we can make sure only one Encryption Plugin can modify the stanza
- Added extension point for setting the lock image. So instead of multiple Plugins setting the lock image, Gajim asks only the currently activated plugin for the encryption status
- Added extension point after clicking the send button, so that a plugin can abort the sending and display some dialogs.
- Added extension point when typing, thats only needed for ESessions now.
- Added a new menu button to choose the desired encryption
- Extend the PluginManager to hold a list of encryption plugins
- Encryption Plugins can register and are added to the new Encryption Button in the ChatControl
- Most encryption/decryption Code is removed from Gajim and now in new Plugins.