api: started work on creating a common API framework

The idea is that this will become a common API framework for both HTTP
and HTSP. And anything else we might think off.

The only real constraint at the moment is both assume a JSON like input
format (for simplicity) since they currently have that in common.
api: started to add idnode to the new API structure
idnode: add new deletion method to allow generic api method
api webui: migrated most of the new web API stuff to the new API subsystem
mpegts linuxdvb: some minor modifications to linuxdvb for better idnode API
webui: updated UI to new API calls. Still crap, but hey ho!