Allow to process raw M3U8 or XMLTV data

[michaelarnauts]

This PR allows IPTV Manager to handle raw M3U8 or XMLTV data next to the JSON-STREAMS or JSON-EPG formats when fetching data from the add-ons. This can be useful when the addon already has a M3U8 playlist or XMLTV file with the data, or when special things need to be added to the m3u or xml directly.

IPTV Manager will only remove the headers, but keep the rest of the data as-is.

TODO:

<tv source-info-url="http://www.schedulesdirect.org/" source-info-name="Schedules Direct" generator-info-name="XMLTV/$Id: tv_grab_na_dd.in,v 1.70 2008/03/03 15:21:41 rmeden Exp $" generator-info-url="http://www.xmltv.org/">