Fixed: XCC was crashing on startup in OS X 10.6

The Lumberjack logging library was using a function not present in 10.6.

This commit reverts to an earlier release that works with 10.6.
Tweaked the parser error messages
Fixed: About window icon was small in OS X 10.6

Previously I was using the app icns file for the image. Now I have a separate retina-ready image for the About window.