use device gray for edges of BDSKEdgeView, looks more like edge colors used by NSScrollView
use device gray for edges of BDSKEdgeView, looks more like edge colors used by NSScrollView

git-svn-id: cb3fc60f0f557b927b8032d8a94e869b6f9f230b@5987 0fceea05-a30d-0410-8a8b-80ef821fb0a1

jasongrout/skim,camillobruni/skim,camillobruni/skim,camillobruni/skim,jasongrout/skim,camillobruni/skim