Ad RAR processing to Torrents

[managementboy]

To be able to use a torrent that has the video RARed, we need to be able to process all files. The same issue was solved by the OSS Hellanzb. The required functions could be copied from the following file:
http://www.hellanzb.com/trac/hellanzb/browser/trunk/Hellanzb/PostProcessorUtil.py

function "def unrar(postProcessor, fileName, pathToExtract = None):"