Update Anathema to Java 8

I have spent some time updating Anathema to Java 8, and would like to merge the changes back to ``master``.
@curttasker, @smattox, are we in agreement that updating is a good move?

Right now, the one thing keeping me is that the latest build of MigLayout is not yet available in any public maven repo. I have  already sent @mikaelgrev a message asking if he would put it there.