adjusting to the change to 'hintgroup'
renamed 'get_single_line_hints' to 'get_single_choice_hints'
add a check for a valid 'hint group' before trying to get an item from that list
add a bit of bullet-proofing: test for correct = 'true' or 'True'
all checkbox test cases are working
move common get_single_choice_hints function up to superclass -- this is a bit of a hack but allows both choice types to use one function
add label="XXX" support to compound condition hints