Save and restore hotkey window arrangement. Also fixes a bug where sessions are too easily divorced (when splitting and setting tab color, they got a divorce, even though the tab color was normally not different). Fixes a bug where you get short-lived-session warnings that you already silenced for divorced sessions because they always got a new guid--the fix is to use the original profile's guid for the warning silencing identifier.
Fix bug where trailing whitespace wasn't stripped according to preference and terminal newlines weren't copied properly either.