Add an option to skip loading state on table refreshes

[etareduction]

When i want to keep the table data live for my users including calculations and aggregates (which makes it impossible to use Cinder.Update for this), I might still want to reduce visual flickering associated with transitions into loading state. Would be nice to have an option (possibly optional argument for refresh_table function) that when passed disables loading state transition and instead keeps showing current data until it is replaced by new data.