Fixed #173: Items disappearing after background run
Fixed #173: Items disappearing after background run

Fixed.  The slave thread code in slave.tcl was set up to read the
master's thread's data only when the thread was first initialized, not
before each advance request.  Consequently, any changes made during the
session after the first time advance would never be loaded by the slave,
and not included in the results passed back to the master.

AthenaModel/athena,AthenaModel/athena,AthenaModel/athena