Added two new loading related selectors: hasBeenLoaded and loadWasAttempted. These selectors allow
end developers to determine if a load has ever been attempted before, which is sometimes necessary
to display the correct information in a UI component. Until a load has at least been attempted, it
would generally be inappropriate to display to the user that there are no Entities X, however as
the current state of each entity currently stands, there is no way to determine that particular
state of an entity. You can determine if an entity is loading or not, which is useful for displaying
a spinner, but other messaging requires more information.