Adding Packagist statistics for repo via Poser badges

Related to https://github.com/Behat/Mink/issues/421
Convert tag names to lowercase for comparisons in JS.
Merge pull request #56 from linclark/case-folding

Convert tag names to lowercase for comparisons in JS
Merge pull request #55 from aik099/packagist-badges-feat

Adding Packagist statistics for repo via Poser badges