ENHANCEMENT Added DataObject::many_many_extraFields() for getting the many_many_extraFields fields for a component name on both sides of a many-to-many relation.
MINOR Added test for many_many_extraFields in DataObjectTest
git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@71613 467b73ca-7a2a-4603-9d3b-597d59a354a9