Nailed the Sunnybeam SDC Datacontrol bug

I think I finally nailed the Sunnybeam SC datacontrol bug. With this bug most daygraph and kWhgraphs from every day get removed because of a conflict with the cache engine and how the SDT files are handled.

I think I have finally fixed it. And it ook a long while to get to this point. At one point I was almost ready to kill the whole cache engine project again.

Luckilly I found it. I will try to fix some more bugs and release a new version to the public soon.