Merge pull request #4 from naneau/master

Cleaning up HMAC
Merge pull request #5 from naneau/master

Adding a simple random string generator
Merge pull request #6 from naneau/master

adding readme
Merge pull request #7 from naneau/master

adding fallback to mt_rand() in random string generation
Merge pull request #8 from naneau/master

updating travis.yml