disable blend mode in inspector for groups without compositing groups
set background colors of table/outline views
-[MgNode withPresentationTime:handler:] shouldn't call -setState:

(doing so triggers the KVO nightmare, even though it's only a transient
change.)
inspector performance voodoo
hacks to stop inspector updating when hidden
don't allow states/layers views to be collapsed by their split view
formalize "!group" MgGroupLayers; added MgGroupCATransformLayer
fix numbering of group names
rename MgGroupLayer.group as "passThrough" (and invert its meaning)
double inspector indent