Refactored the plugin code and XMPP pre-binding:
- Simplified XML request sending and removed duplicated code
- Added debug output and error reporting
- Send separate restart command before bind
- Use more Roundcube plugin API features
- Moved config template to config.inc.php.dist
- Made configuration options more flexible
- New option to use chat without prebinding
- Updated to latest converse.js version
- Add localized texts
Update converse.js submodule reference
Don't show chat in popup windows