Removal of Ashland Treatment and DISTID field

[bettinardi]

Now that we are moving forward with a calibration without a special treatment for the Ashlad district, is it possible to remove the "DISTID" field from Visum / the ABM?

I see on line 606 of SOABM.py that DISTID is specifically called out, but is there away to check if the ABM code actually uses that field now?

In general, as we are addressing #40 (checking all inputs), perhaps we can look through the fields and remove any field that isn't actually being used by code. When developing an input check for each input field, we will want to know how the code is using each field and what valid inputs are to check against.