.csv upload for bulk user custom field changes

[pfaffman (Jay Pfaffman)]

One column must contain the user_id (not username ). Custom user fields have internal names like user_field_1 , so the other columns need to have those as column names.

Column 1	Column 2	Column 3
user_id	user_field_1	user_field_3
4	value	hello
3	another value	world
6	still another	banana