More robust handling of childViews in recomputeIsVisibleInWindow.

Clone childViews before iterating over it so we are guaranteed it won't
change during the iteration.
Fix indexing problem in SC.CollectionView.

The index check here was comparing idx, an index into itemViews, to len,
the length of viewsToRedraw.

I removed the index check since if the index is out of bounds, the result
will be undefined, which insertBefore treats the same as null.
Call notifyPropertyChange on currentStates when statechart is destroyed.

The currentStates property was remaining cached after the statechart was
destroyed. This meant that when respondsTo was called, it would still
iterate through these now destroyed states, causing a crash.
Revert "Check isDestroyed in respondsTo to avoid crash."

This reverts commit ee3d14cac4c01874b9f07c4a2b914042e876c850.
Make modal pane fill entire window, regardless of scrolling.

If the browser window was sized so that it could be scrolled, the modal
pane was sized the same as the browser window, so scrolling would reveal
the content under the modal pane.
Add the ability to specify isDefault and isCancel for SC.AlertPane buttons.

Conflicts:

	frameworks/desktop/panes/alert.js
Make SC.ScrollView take scrollbar visibility into account when resizing.

After a scrollbar visibility change, re-check the dimensions to take it
into account.
Bumping to SC 1.9.0.8.