OSC 7 integration

OSC 7 escape sequence is used to tell terminal the current working directory, so that terminal emulators can open new windows/tabs at the same directory.

It can simplify the workflow to choose and open a directory in new terminal window, if broot can emit OSC 7 sequence when it navigated to other directories (and reset it while quitting).

EDITED: Made a mistake. It's OSC 7, not OSC 8.