This change implements the use of integer id's that are now supported by the new version of ARGUS TV

This is a big change for the better. In the past every unique entity within ARGUS TV was identified by a GUID. While this works great, it provided an awkward match with the way XBMC likes to identify unique entities by the way of integers.

ARGUS TV v2.1 implemented unique integer id's in addition to GUID's. 

Using these I could remove a lot of 'smart-ish' matching and mapping code. It is not perfect yet, but way (!) better than it was before. Notably the id's of channels and timers are now guaranteed to NOT change after shutting XBMC down and re-starting it. They stayed the same most of the time before, but this was very fragile and easily broken when the user made changes to channels, channel groups, channel ordering etc. within ARGUS TV .

I hope this can get merged soon so that users can report any rough edges left.