Added function to find what ladder(s) a lesson belongs to (Issue #1822922, will be used for #1772560)

Hardened the update function to make sure the field_collection module is enabled and revert the Ladder feature to ensure that the fields are created (Issue #1822922)

Added field formatter to display field collection as a ladder and adjusted the output HTML (Issue #1822922)

Switched the curriculum-to-ladder node conversion to hook_update_N() since it will only need to update existing sites (Issue #1822922)

Some more work to allow Maintainers to flag lessons within a curriculum as provisional.  This commit has been split somewhat arbitrarily to divide credit between g.oechsler and Alan Evans and extra caution should be taken if a revert is needed.

Georg Oechsler authored Aug 26, 2012 and Alan Evans committed Aug 26, 2012

Initial work to allow Maintainers to flag lessons within a curriculum as provisional.  This commit has been split somewhat arbitrarily to divide credit between g.oechsler and Alan Evans and extra caution should be taken if a revert is needed.