Delors/BAT — pull request #5 by Blaisorblade (2012-02-25 00:13:42+00:00)
Title: FIx NullPointerException

I got a NPE when using ObjectType.
Object.equals(null) must just return false; the semantics of pattern matching is such that the new code is correct (I also tested it).
Here I follow Programming in Scala, chapter 30, but I make things simpler since ObjectType is final.