bump default aws version
Update README.md
Update Gemfile

Added pessimistic versioning for two newly problematic gems.
Merge branch 'develop'

Conflicts:
	Gemfile
	README.md
Merge pull request #5 from NREL/develop

Develop
Merge branch 'develop'
Merge branch 'master' into develop

Conflicts:
	Gemfile
Merge branch 'develop' of github.com:NREL/OpenStudio-analysis-spreadsheet into develop