Loading indicator, WatchdogTimer

The loading indicator shows up when data is being loaded, or when a
query is executing.  The WatchdogTimer helps us gate query execution
in the nickname keyup handler, so that the input remains responsive as
the user types.
Fixed use of loading indicator

By adding a window.setTimeout(..., 0) to our query execution pipeline,
we give the initial loading.show() time to render to DOM.

If that doesn't make any sense to you, read:

https://stackoverflow.com/questions/779379/why-is-settimeoutfn-0-sometimes-useful