Add inner- and outer-loop to Direction enumeration

[mark-mockett]

Summary

"Inner Loop" and "Outer Loop" directions are included in the TMDD but were not added to WZDx previously for an unknown reason. This issue is to propose adding those values to the Direction enumerated type.

Motivation

A couple states sign loop highways only as "Inner Loop" (for travel clockwise) or "Outer Loop" (for travel counter-clockwise). These two values are included in the TMDD but not in WZDx. It's cumbersome and inaccurate for those data producers to translate the direction of a road event occurring on one of these roads to conform to a north, south, east, or west direction, and may be unclear to data consumers when matching events to their maps.

Proposed changes

Add inner-loop and outer-loop to the Direction enumerated type.

After the change (and pending addition of unknown and undefined), the Direction type could look like this:

Value	Description
northbound	Road flow is in the northbound direction
eastbound	Road flow is in the eastbound direction
southbound	Road flow is in the southbound direction
westbound	Road flow is in the westbound direction
undefined	Road flow does not have a signed direction. For a RoadEventFeature, the first and last coordinates in the feature's geometry represent the beginning and end of the road event in the direction of travel it impacts.
unknown	Road flow may have a signed direction, but the affected direction of travel is not known
NEW inner-loop	Road flow is in the clockwise direction of a ring road or beltway..
NEW outer-loop	Road flow is in the counter-clockwise direction of a ring road or beltway.

[lynnerandolph]

The TMDD documentation does not appear to have any comments or extra information related to inner or outer loop.

[lynnerandolph]

Also, I note that there is both a direction and an alignment--alignment is where the inner/outer is allowed.

[j-d-b]

Resolved in #356.