Better error message when interval doesn't exist in file
Issue #2
new
If a request is made for an interval that is not in the dataset, for example 'daily', but only 'monthly' and larger is in the file, the current error is:
*
* The label specifications matched no records in the binary file
*
This incorrectly points to a problem with the label.
Summary: Test for existence of the interval and if not available print out appropriate error message.
