Cleanup of shutdown of event contexts
- centraly mark citcontexts connected to AsyncIO structs for deletion
- free AsyncIO members in FreeAsyncIOContents() and make shure its called all over the place
- sort stopping of contexts by type
- close our DB/event - add pipes on exit
- reshuffle RSS Aggregator; all parsing etc. to rss_atom_parser.c, all free/start/stop to serv_rssclient.c
- remove unused stuff now discarded from the rss header
- rename all instances of the rss aggregator struct to RSSAggr