Error in Shipments Table script

[ColSmith76]

Unfriendly errors in script that cycles through the PMG outputs and recombines into the shipments table. Suspect it is data type related. Need to resolve before new release created as model does not currently run through end of supply chain section.

[ColSmith76]

Add fixes that resolve this issue to repo. Include check code to look at consistency by market between the each step's output and the final shipments table to flag any simulation problems at the market-SCTG level