Merge pull request #6 from openc/schema_enhancements

Schema enhancements
Add description for con_date in PreviousName
Add spec example for more detailed share_parcel data
Merge pull request #7 from openc/share_parcel_dates

Add spec example for more detailed share_parcel data
Merge branch 'master' into company_schema_improvements

Conflicts:
	spec/sample-data/valid/company-45.json