refs #92,#93 Undo previous hack, instead, let's let the model update
itself via the BoardManager, and fix the server where the problem really
exists.  The server only deleted the question from the model where the
students receive their questions from, but not from the model where the
teacher app gets its data.  Confusing, yes, but we should have been able
to debug this by just looking through the teacher and server.
refs #91,#95 Fix for deletion handling where we were not checking for
any error conditions.  This should be revisited in the future to beef up
JSON handling (I don't parse the JSON from the message body).  For now
we just toast the thing if we succeed or fail.  Let the model update
things.
[#95] Cleaning, removing comments, merging duplicate constants in the same file: Constants.java