Add description of income types to the onboarding form
Add description of income types to the onboarding form

This addresses the problem described in #151.

adelevie/districthousing,dclegalhackers/districthousing,codefordc/districthousing,uncompiled/districthousing,dclegalhackers/districthousing,uncompiled/districthousing,jrunningen/districthousing,dclegalhackers/districthousing,adelevie/districthousing,jrunningen/districthousing,MetricMike/districthousing,dmjurg/districthousing,codefordc/districthousing,adelevie/districthousing,codefordc/districthousing,MetricMike/districthousing,lankyfrenchman/dchousing-apps,lankyfrenchman/dchousing-apps,lankyfrenchman/dchousing-apps,meiao/districthousing,adelevie/districthousing,dclegalhackers/districthousing,lankyfrenchman/dchousing-apps,dmjurg/districthousing,uncompiled/districthousing,MetricMike/districthousing,jrunningen/districthousing,meiao/districthousing,jrunningen/districthousing,jrunningen/districthousing,codefordc/districthousing,dmjurg/districthousing,uncompiled/districthousing,MetricMike/districthousing,uncompiled/districthousing,meiao/districthousing,meiao/districthousing,codefordc/districthousing,meiao/districthousing,dmjurg/districthousing