Implement exporting all results, with one file per variable
Implement exporting all results, with one file per variable

This outputs one *.tab table file for each variable in the Pyomo model.

I tested this manually by running all of the examples.

bmaluenda/SWITCH-Pyomo-Chile,bmaluenda/SWITCH-Pyomo-Chile,OCM-Lab-PUC/switch-chile,bmaluenda/switch,OCM-Lab-PUC/switch-chile