Add a method for taking interior + exterior modifier sets and making an offset model for daylight

[chriswmackey]

Mostapha and I talked about this a while ago and I'm just documenting it in a public place because I think it should be implemented at some point.

At the moment, each Honeybee geometry object gets only one modifier, which is consistent with the fact that each Radiance Polygon gets one modifier. However, there are a lot of cases where we want to have different modifiers on different sides of a Honeybee geometry (eg. an exterior reflectance that is different from an interior one). So it would be nice to have a method that can take two modifiersets (one to be applied to the interior and another to the exterior) and a room-based model. The method would duplicate and offset all of the Honeybee Room Faces one such that one of them gets the interior modifier and the other gets the exterior one.

This is what we currently use within the thermal comfort maps in order to translate EnergyPlus constructions (with different interior/exterior reflectances) into a format that can work with the Radiance calculation. It's also used to ensure that adjacent Floors/ceilings in honeybee get distinct modifiers from one another.

I think the major difference between those existing implementations and what we might do here is that we might want to expose things like exterior_wall_thickness, interior_wall_tickness, ceiling_thickness, and floor_thickness as options, which let people control the offsetting behavior so that they can get as close to the real building as possible.