Fix activity page bugs

Fixes a bunch of issues I uncovered while digging into another bug (which @nodesocket already fixed!).

* Doesn't refresh if an array hasn't finished loading yet (this was causing duplicate transactions from time-to-time on the transactions view)
* Fixes the model hook to work properly for the transactions page (wasn't displaying transactions on login before)
* Sets up the current marketplace during the model hook as well as the setupController hook (was causing some auth timing issues)
* Gets the API key secret from the login response rather than making another API call to find it