Add exception throwing assertions

Hi Josh,

Here are two commits for checking ARM in the face of exceptions.  The first commit passes the unit tests because ARM works, but the second fails because close()'s exception is not propagated to the caller if the body doesn't throw, which is different than how JDK7's try-with-resources works.  See http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.20.3

BTW, is there a better place to discuss this than in a pull request?

Blair