2.51.03: More interiors data; improve retrofit timing; expand EPD model

This update includes a minor expansion of the interiors data, more detail in the EPD model, and the capability to model retrofits happening in years other than the first year of analysis. 
Additional Interiors Data
We have added additional data on wall assemblies as well as correcting some of the naming on single-sided assemblies previously in the assemblies DB. 
Expand EPD Data Model
The industry-wide EPD model was expanded to additional fields.
Decouple year_completion
 from the beginning of the analysis
In this update, the user can pass year_completion
 to describe when the project is completed as a separate parameter from year_analysis_start
. This allows better modeling of future retrofits by allowing users to model benchmark energy use for a building pre-retrofit, then model the retrofit in the given year. 