When a User is Editing a Component, display that on the Component's page.

When viewing a Component, it would be useful to know if someone is editing it (and who that User is). Not only would that indicate that the information being viewed is subject to change, but it would also help the case where two people end up editing the same component at the same time. Currently when that happens, whoever saves their edit second loses their changes because their save will fail and they'll need to refresh the page.