Added +=, -=, *=, and /=
Finalized the coding for the specialized assignment options for the LET directive. While we did the array assignment with this change we did not include the string template variables for the assignments since this will need to looked at longer term.
During the coding we reviewed the current array assignment functions in the system. MSB only supports assignments on full arrays — not ranges. I will need to come back to this logic later to add in range assignments.
