[fractal] (14 commits) ...Use is_empty instead of != comparison

[Daniel Garcia Moreno <danigm src gnome org>]

Summary of changes:

  6d123a2... bump gtk-rs & gstreamer crates (*)
  09096a0... replace all the new_from with just from_ (*)
  ccf3b2b... EntryExt: get_text returns a GString now (*)
  d7d7da6... column: libhandy::Column is now a proper Container (*)
  5ee2033... use new gdk::Keys API (*)
  9d4d0b4... use letter-avatar from a fork (*)
  687bad3... WidgetExt::destroy is unsafe now (*)
  c7a5c32... use released crates (*)
  ab3077e... use the new keyval api (*)
  63ee165... divider: replace the unsafe destroy (*)
  7d3bfd4... Fix rebase conflict bugs (*)
  35bd387... Remove unsafe use for widgets removement (*)
  eee81cc... fix related cargo warnings (*)
  59d8c91... Use is_empty instead of != comparison (*)

(*) This commit already existed in another branch; no separate mail sent