preserve nodeunit semantics a bit better

Hello me, 

Please review the following commits I made in branch 'nick-first'.

07eb4bae962030906ac53c97e03359c24c1c947c (2013-06-12 11:49:34 -0400)
version bump

e9b76ad05f920d367e762bff5dbbaccba91df457 (2013-06-12 11:48:33 -0400)
Preserve 'this' correctly in nodeunit tests. Call test.done() even if the function throws.


R=me