Tests and more tests

    Switched to Mocha
    Fixed missing documentation
Support for custom regex matching background
Respect original quotation around image url
Support for limiting sprite size from options
Fixed custom RegExp documentation
Fixed minified test
Merge pull request #10 from crudo/versionDoc

Support for limiting sprite size from options
Fixed grunt dependency
Merge pull request #11 from crudo/c-gruntFix

Fixed grunt dependency