added FieldRowPanel from @kaedroho 5dc7a220f8799a7c6871b119724f7e07cb54f4fb
corrected commit ref to kaedroho@5dc7a220f8799a7c6871b119724f7e07cb54f4fb
refactored how classes are applied by edit handlers. replaced inconsistent name 'classes' on settings tab. misc tweaks to improve layout. Merged FieldRowPanel concept from davecranwell#327