Fix addition (make it associative when dealing with one array arg).  Fix unary minus operation when dealing with array results.  Fix Sumproduct on some use cases. Fix handling of cell ref ranges in formulas. Added unit tests for all of the above.
Fix addition (make it associative when dealing with one array arg).  Fix unary minus operation when dealing with array results.  Fix Sumproduct on some use cases. Fix handling of cell ref ranges in formulas. Added unit tests for all of the above.