remove WINDOW_STATUS, simplify adding and selecting chat windows
reduce number of windows, use consistent naming
remove callback introduced temporarily during refactoring
Merge pull request #479 from krisl/internalise_window_handling

remove WINDOW_STATUS, simplify adding and selecting chat windows
INSTALL.md: cd to the previous directory after installing libsodium
Merge pull request #488 from kongr45gpen/patch-1

INSTALL.md: cd to the previous directory after installing libsodium