Limit the number of versions in the combined graph results for each test, using the semantic version info.

[MaartenHilferink]

If the last semantic version number is A.B.C. I'd only like to see earlier patches X of A.B.X, the last patches of earlier minor versions of A, and the last patches of the last minor versions of earlier major versions. Other versions don't need to be included in the results for A.B.C.

Originally posted by @MaartenHilferink in #17