Completed DepthProfileData function (pending team discussion on particular functionality); updated UpdateUnitRef function to read WQX MeasureUnit domain list from the web

To discuss at the next team meet:

• Depth measure value fields are of class "character," but to do the conversions they must be numeric. Right now the function is coded so that the data is changed to numeric, but that generates a warning that some values are coerced to numeric (this warning is suppressed in the function). Do we want to keep it this way? If not, we can implement similar logic that we use in the ResultValueSpecialCharacters function.
• In the sample data I've been using, it looks like they may use the ActivityDepthAltitudeReferencePointText field to record values. It's a text field, but this brings up a potential use case where users rely on one of the depth measure unit fields to know which unit the altitude reference point refers to. This is problematic because when convert = TRUE, the measure units are changed.
  • We should confirm that this use case exists, but even if it does, I think this is too specific of an issue for us to address, particularly at this early stage.