medialibrary: Respect the fdo spec to find thumbnails
medialibrary: Rework the way we sort files in the view

We do not care about the case and the full path, but we only care about the basename
of the uris (with the same case)
mainwindow: Explicitely update application title when needed

That broke when we stopped calling _syncDoUndo(), disabling a bit more
undo/redo
project: use quote_uri before all URI to be added to a project
ui: Do not crash when trying to sort a DiscovererInfo sublcass we do not support
project: Make use of the new API to get total number of asset in a project

    + medialibrary: Make sure to take into accound currently loading assets
      when conneting to a new project
    + Make sure not to introduce multithreads in GES