Error checking in SVGKImage to see if CALayerTree creation succeeded.
Don't try to call functions in SVGKLayer when setting an image.
Warn the user when they select Reinel_compass_rose that it might break the program.
Some minor tweaking time.
Merge branch 'master' into arc

Conflicts:
	Source/QuartzCore additions/SVGKLayer.m
	Source/SVGKImage.m
	XCodeProjectData/Demo-OSX/SKAppDelegate.m