[Ide] Initial support for sliding pads on windows
[Ide] Fix focus issues when showing pads as NSWindow children.

Work around the focus issues by switching to WindowType.Popup and showing the window
*after* we add child. However, realizing the window before it's shown causes it to
appear at the display origin and then get moved into the desired location when we
show it. This causes a highly visible flickering issue. There isn't any apparent want
to prevent this, so we're masking the flickering using an opacity trick.
Revert "[Ide] Fix focus issues when showing pads as NSWindow children."

This reverts commit 8019759c829d5ed345f48c655622a6c838270d34.
Set TypeHint to Toolbar *before* calling AddChildWindow().

With the Toolbar type hint, GdkQuartzWindow returns NO from
-(BOOL)canBecomeMainWindow and YES from -(BOOL)canBecomeKeyWindow
Merge remote-tracking branch 'origin/master' into sliding-win-pads
Merge branch 'master' into sliding-win-pads
[Ide] Fix sliding pad resizing
[Ide] Improve behavior of sliding pad resize

Use NSWindow.SetFrame to move and change the size of the sliding pad
windows all at once. This reduces window bumping a bit. It is not perfect
but good enough for now.
[Ide] Auto-hide pads when we start to resize.
Merge branch 'master' into sliding-win-pads
[Mac] Fix pad resizing issue

Properly place pad windows when resizing. Fixed for the case of
having multiple monitors.