Import Cross Sections Template Requires RiverDistance

[philipbaileynar]

The cross section template for databases that identify cross sections by ID now includes the RiverDistance column. This should not be necessary given that the whole point of identifying cross sections by ID is to eliminate the need for the RiverDistance column. Version 1 of the Cross Section Viewer did not include this column in the template.

@JohnShelley note that removing the RiverDistance column from the template will mean that the import templates can only contain data for cross sections that already exist in the receiving database. In other words, if the import template contains cross section IDs that do not already exist in the receiving database then the import process will fail with an appropriate warning.