Changes

Remove prev. Insets impl

NativeWindow: Add new Insets/InsetsImmutable

Unify Immutable/WriteCloneable Usage ; Remove Clonable for ImmutableOnly types

NativeWindow/NEWT: Refine Insets definition for size and position, read and write access

NativeWindow/NEWT: Cont. refinement of Insets usage

Completes commit d4670328991c02a6f11f8873ea7a2331f17d0ef0

NEWT/Window/Insets: Implement proper Inset usage ; Cleanup WindowImpl::reconfigureWindowImpl

Implement proper Inset usage (window decoration size)
  - Insets are either polled (updateInsets()) or event driven (insetsChanged())
  - Insets are used for size/pos calculations from Java side
  - Natural size/pos in NEWT is client-area, ie w/o Insets
  - Adding setTopLevelPosition()/setTopLevelSize() for top-level values,
    ie including insets

WindowImpl::reconfigureWindowImpl
  - Use flags to pass down the requested action to the native implementation
  - Impl. all native actions: visible, decoration, reparent, resize, fullscreen
  - Always use size/pos in client-area space, impl. shall use Insets to tranform them
  - Remove double-setting of (reparent/fullscreen), which where introduced due to buggy impl. code
  - Fix return from fullscreen position: Was overwritten with FS position (0/0)
  - Fix decoration change: Remove visible toggle - not required, and actually disturbing

X11Windows/WindowsWindow: Added/Fixed Insets impl.

Tests (manual):
- TestSharedContextVBOES2NEWT utilizies proper window layout using Insets
- TestParenting03bAWT uses window layout for reparenting

test scripts