Conversion framework/Filetype resolution

So, filetype resolution involves matching a filetype to an app, and the conversion framework sits between that when there is no app avalable to open that format. This is 100% seamless and invisible to the user.

Each converter will be a php script named "old-to-new.php". so converting an opendocument text file to html would be called "odt-to-html.php"

Most formats are many different files compressed into one file. So, in order to convert to HTML, we make a temporary directory to keep pictures and meta files in. Then when it's sent to the server to save, the files used in the document can be copied and re-compressed into the archive. Once everything is done, it deletes the temporary dir with all the document's files.

So, we need to evaluate some php conversion classes, pick out which ones are the best.