Merge pull request #8 from ackerdev/master

Replace vendor PNGs with SVG export versions
Revert "Change green used in '4.0' badge to '3.0' green"

This reverts commit d41b039f3f51483d037d5c36972d37a3973a9ab0.
Add all Code Climate variations

As delivered to Code Climate, all iterations of the shields from 0.0
to 4.0, with an unknown '?' version.