Tile/Wrap Windows Settings Inconsistencies

Related to #504 (closed).

The only way to set "wrap_windows" now is via xfconf. As noted in #504 (closed), tile_on_nove and wrap_windows are either/or. If tile_on_move is checked in GUI settings and wrap_windows then set via xfconf, one can now wrap windows. However, once the Tweaks dialog is opened again, the wrap_windows setting is automatically reversed (due to tile_on_move being checked). The proper way now to wrap_windows is to first uncheck Automatically tile... then issue xfconf command. This is somewhat un-intuitive.

If tile_on_move and wrap_windows are either/or, then maybe gui setting should be a switch between the two. If third option exists (e.g. neither wrap nor tile), then some sort of dropdown might make sense.

Running latest version of xfwm4 from git.