"Fix" releasing the mouse button over a window.

Previously if you click-drag-released the left button on the root window to a client window,
Openbox would ignore the release because we don't own the client window. Now check if we
are in a button press or not before ignoring it. The bug was we would initiate a move when
the cursor was moved over a titlebar even when the button was unpressed because the variable
didn't get cleared properly.

This fix is very ugly.
This might be a little bit better.

At least it consistently doesn't run the openbox action.
Only warp on menu close if it was also the top level menu.
Start on the second entry...
Allow specifying several mousebinds in one go (hack)

Doesn't handle trivial stuff like multiple spaces, it's 3:24am so no guarantees otherwise either.