Create helper function ko.utils.objectForEach to interate over object properties/values. Use the new helper function instead of for..in loops everywhere.
revert ko.toJSON change.
Swap order of key/value params in objectForEach for consistency with $.each
Partially revert change to postJson
Merge branch '687-add-objectForEach' of github.com:SteveSanderson/knockout into 687-add-objectForEach