Scrape, validate, and have fun with CITATION files

We should check for CITATION files. When we find them we may want to check if they follow one of the standards and look at the content. One interesting case would be if a doi can be found in a CITATION file. We could compare this with the doi of the paper we are working on, if the two dois match I think we can be fairly sure that we've got the paper that describes the software.