Save summaries in core_summaries

Save summaries in core_summaries rather than just summaries subdir
Pandas needs to be installed

Put it on its own import line
New file to summarize scenario in model context

To run on modeling machine
Merge branch 'master' of https://github.com/MetropolitanTransportationCommission/Travel-Model-One-Utilities

Conflicts:
	CoreSummaries/CoreSummaries.Rmd