Category names and groups in item list (and custom categories)

Add category names to colors (already a high voted item).
Also split item list into category groups with the name/color as the header of the group.
Allow ability to add custom categories/colors which would help to further customize individual Lists (i.e. it would result in sub lists within a list):
For example a Shopping List named General Shopping could contain items under groups such as Veggies, Drinks, etc and Automotive Shopping List could contain items under groups such as Maintenance, Performance and so on. Possibilities for this could render the software limitless!