Normalize library loads to fit project needs

[praftery]

For users who have a real project in mind but don't have measured/simulated load data, it would be useful to be able to scale the closest fitting building in the library to more closely match their building. This could easily be done by normalizing based on building area, or peak heating load, or peak cooling load. Any one of those is a much simpler datapoint to get at than timeseries load data - at the very least building area should be readily available. Doing this normalization would mean that the equipment sizing and emissions results would be more relevant to the actual project.

[t-kramer]

Covered in PR #146

[praftery]

I think scaling by area should apply the scale factor to both heating and cooling loads, but scaling heating and cooling loads should just apply to just that specific load. That allows users to increase heating relative to cooling or vice versa. I'd just add some descriptive text explaining what the multiplier gets applied to for each option.

This functionality already exists for the base load.