apparently functional get_next_uncertain_sentence
imported method for invoking editation of uncertain sentence
kinda working autostop

to do:
- stop when window reached;
- play once through;
- signal the stop in a friendly way;
- (smaller chunks by exploiting long sils via -palign)
overhauled m.edited_subs

- no $elements are stored in model any more;
- switched added switch to autostop;
Now autostopping when window reached
removed dummy write function for edited_subtitles.str
Now automatically playing the selected window
small bugfix
Merge branch 'uncertain_sentences'
autostop debug

- now giving more time for the autostop to start;
- no longer deleting autostop mark on pause;
- autostop no longer throws selection collapse error;
overhauled the editation mode interface

- the other elements now stay visible but overlaid;
- the subs now get animated down on editation start;
- textarea with edited subs now unwraps the observable;
- TODO: do the edited_subtitles_str still disappear???