Improvements and fixes

Combiner boxes, irradiation sensors and feed-in meters now name the data logger they are read from. An older device reached through remote access no longer asks for a login over and over.

• Combiner boxes, irradiation sensors and feed-in meters now show the data logger they are read from.
• An older device's own web page, reached through remote access, no longer asks for a login over and over.
• Adding a data logger now reports when its test read keeps failing — a missing login, for example — instead of showing nothing.