* - RaggettInternalHHVM: Use the limited-functionality HHVM extension
* - RaggettInternalPHP: Use the PECL extension
* - RaggettExternal: Shell out to an external binary (tidyBin)
- * - Html5Depurate: Use external Depurate service
- * - Html5Internal: Use the Balancer library in PHP
* - RemexHtml: Use the RemexHtml library in PHP
*
* - tidyConfigFile: Path to configuration file for any of the Raggett drivers