Re-create the zoning_heights table

[hanase]

There are two issues with the table:

• a set of plan types included in the parcels table do not have corresponding records in the zoning_heights table;
• the max_far column seemed to be truncated to integer.

Another issue is how the proforma model interprets the rows. For a parcel that allows both, res and non-res, the model takes the far derived from the minimum of max_far, max_dua and max_height. This should be changed in the model.