Bugfix.  If the date range was chosen before clicking on a FOI/offering, then that chosen date range was "forgotten", because a FOI/offering selection initialises a new selected item.  Now, when checking that we have the required parameters to plot, we ensure that the current item is updated with the latest values from the datepicker controls (rather than only on the datepicker change events).
Bugfix.  If the date range was chosen before clicking on a FOI/offering, then that chosen date range was "forgotten", because a FOI/offering selection initialises a new selected item.  Now, when checking that we have the required parameters to plot, we ensure that the current item is updated with the latest values from the datepicker controls (rather than only on the datepicker change events).

52North/sos-js,52North/sos-js,paul-breen/sos-js,52North/sos-js,paul-breen/sos-js,paul-breen/sos-js