Fixed bug: message receive blocks had not been replying with what
block to execute next.  This commit fixes that problem.

Added tests to ensure that message sequences would alternate correctly
and update peered data on both ends.
Had a bug in which when passed in arguments to message sequences,
would not send the sequence local data to the other side unless the
sequence local data were modified in the sending function.  Made it so
that the first message of a sequence can explicitly force copying
sequence local data over to other side.
Beginning of a few tests to ensure that system is handling sequence
local data properly.