Setting the default icon name causes that it's applied globally to all
newly opened windows in the process, not just for the applet's windows,
so it cannot be used if the applets are built as in-process.

The translation domain needs to be set before loading GtkBuilder files
to get the translated strings when the applets are built as in-process.

Add a new preference to force fixed size on all notes to prevent
resizing. Also fix a bug where notes taller than the screen height would
not display scrollbars after applet restart.

Fixes #370

Don't use that value uninitialized