Data file sanity

It shouldn't have been a problem before because file handles, but this makes sure it's not a problem by preventing more than one thing from writing to data.yaml.  (Also I don't know how much I trust that first thing, seeing as it's failed me once (out of many times, but that's still more than zero) and apparently you once as well, so...)
If you experience further corruption/missing data/whatever, please ask me what the wtf that's about, and I'll likely wtf with you and then go off to see if I can figure that one out.