Desktop: Tool to populate the cache database

[davidrg]

Fetching the entire dataset for some stations can take quite a while. It would be nice to have a separate tool that you can use to fetch all available data for a station into the cache DB. This could be a console tool or a graphical wizard. Or both.

This would rely on #41 The Great DataSource Refactoring or perhaps #27 if the solution there is to refactor the reporting (and therefore the data layer) out of the main application.