ReadWaterML2 - some tests failing when using the API to read instead of parsing the DOM

[smalers]

Some tests are failing when using ReadMethod=API to read daily and instantaneous data. Because this is NOT the default, fix when there is time.

[smalers]

The WriteWaterML2 command test using the API to write is also failing. Again, this is not the default so it is not critical to fix.