Namely: * When cursor is between end of output and end of file, some shortcuts start behave differently: 1) Enter commences from wherever. 2) Escape cleans the input. 3) Movements to the left (left, shift+left, home, shift+home, backspace) start treating end of output like beginning of file. One can still use other movement keys or mouse to escape from this virtual wall. * Special treatment of the "cls" command (probably, should be configurable). * REPL history navigation automatically scrolls the view to make the input visible. Also: * Added "repl_kill" command to enable Ctrl+C-ing. * Added "repl_external_id" to view settings. * Added "view_id" parameter to "repl_open", so that one can reuse the same REPL view multiple times (e.g. to re-launch an interpreter after ctrl+c).