Reset gradient layer when frame and/or size changes, as the different methods don't go through a common setter.
Reset gradient layer when frame and/or size changes, as the different methods don't go through a common setter.

git-svn-id: 765db44a9620ed55f4f8addfd3c14fe8cd57f6bb@4013 0fceea05-a30d-0410-8a8b-80ef821fb0a1

nanoant/Skim,nanoant/Skim,nanoant/Skim,nanoant/Skim,nanoant/Skim