Test for any RTI element on the POI model

Previously RTI would be added, now it defaults to []
Updated MapView to deal with rendering a POI without location info

Added a helper function to POIModel for hasLocation
Set a default attribute for while a POI is being requested
Render the detail view before the POI has loaded

Now we link to POI's from the today view this becomes more important.
Render DetailView once loaded
Set an attr on the model whilst a request is mid-flight

Done by overriding fetch and listening for sync/error which
are triggered on success/error respectively
Moved to the general midFetch solution
Added general solution to rendering errors

Base ErrorView which takes a message and renders it to the
specified el. Can be rendered on model 'error' event.
Merge pull request #44 from ox-it/detail-view-load

Detail view load