Set buttons sensitive depending on if the page is complete

Use get_page() instead of page specific methods

This avoids being able to open multiple ChatControls for one contact.
Historically, this was used to send a message to a specific resource.

Functionality has been moved to Accounts

- Make handler private
- Fix pylint errors
- Access widgets directly via builder

- Remove ApplicationWindow form glade file, we already inherit form ApplicatonWindow
- Make some methods private
- Fix pylint errors

- Rename methods
- Make methods private
- Fix pylint errors

- Make methods private
- Rename some methods (shorter names)
- Fix pylint errors

Daniel Brötzmann authored 5 years ago and Philipp Hörist committed 5 years ago

This enabled the user to directly add a setting without having to add
a theme first.

Daniel Brötzmann authored 5 years ago and Philipp Hörist committed 5 years ago

When adding a new theme, it is automatically applied. This enables users
to view their changes directly without switching the active theme in
Preferences first. Deleting the currently active theme will fallback to default.