NEWT X11Window.c: Cleanup Code - No changes.
Bug 924: Fix 'Unity WM' issue w/ sticky _NET_WM_STATE after Fullscreen On/Off Cycle

Unity WM keeps the _NET_WM_STATE (_NET_WM_STATE_FULLSCREEN, ..) after fullscreen-exit
even though _NET_WM_STATE_REMOVE was issued.

Add remedy: Reparent Child -> TOP: Reset _NET_WM_STATE (! _NET_WM_STATE_FULLSCREEN, ..).
Bug 924: Ignore reparent when in fullscreen - otherwise may confuse WM
Bug 924: X11 WindowDriver: Only perform 'tempFSAlwaysOnTop' toggle @ focusChanged(..) if isFullscreen()

.. otherwise it will be triggered by reconfigure tasks while enabling/disabling fullscreen.
Bug 924: Remove position criteria from reparent/fullscreen success, WM's only regard custom position as a hint (X11).
NEWT WindowImpl: Enhance insetsChanged(..) DEBUG output
Bug 924: More robost Fullscreen Exit

- 'tempInvisible' shall be also performed for top windows, solves Unity-WM background refresh issue

- Rename local field 'fullscreen' -> '_fullscreen' to avoid confusion

- Proper insets handling: Set 'WindowImpl.this.fullscreen = _fullscreen' only before reconfiguring,
  otherwise wrong position maybe used due to wrong insets value.

Tested w/ WMs: KWin + Unity