make expand postContainer more easier

If user don't know drag to expand and move 0 after down, then think user clicked and toggle postContainer's height between max and default 400.
Merge branch 'patch-3' of github.com:mani95lisa/NodeBB into mani95lisa-patch-3
fixing space-indentation, modifying behaviour a little bit so that the maximized position is not saved, and minimizing can return back to the previous saved position