import task for insurance data #165
added is_visible flag and import task for hiding datasets, displaying demographics and select insurance stats on map page
updated insurance data source
added insurance import task to all import
implemented insurance views by age and by race #165
showing 5 breakdowns of health insurance data
added source link for health insurance
Merge pull request #167 from datamade/master

health insurance by age, race, nativity, school enrollment and income