When updating a roster entry, include it in the callback invocation

This allows finer-grained tracking of roster changes by observers.
[#77073002] Fix IE9 errors in Strophe.muc
Merge pull request #35 from jaygeeseman/fuck_ie8

Fix IE9 errors in Strophe.muc
Merge pull request #33 from benlangfeld/feature/include_updated_item_in_callbacks

When updating a roster entry, include it in the callback invocation