Added code to show a No data message in the legend when data is requested but no data is available for that time period.

Removed display of non selected methods and updated to call showDataIndicators when any control changes the displayed data regardless of whether data is fetched.

Fix setting of initial method id

Adding some selectors and a function to help implement the no data overlay and other no data messages.

Wdfn 508 - Default methods to the one with data

Need to set the selectedIVMethodID regardless of whether showOnlyGraph is true or false. This will fix the issue with WDFN-504.

Wdfn 504 - Changes made to clean up hydrograph rendering and to make it possible for the graph server to determine when the hydrograph rendering is complete

Wdfn 500 download links refactor

Updated to cleanup with hydrograph line rendering and to create a consistent set of elements that will be rendered that can be used by the graph server to determine when rendering is complete.

Wdfn 502 - Implement loading indicators when loading data for the hydrograph