[mythtv] Better Integration of plugins

[Paul Volkaerts]

As I mentioned a while back; I have prototyped a few changes to the OSD that
improves the integration of plugins.  The code isn't that extensive but the
architectural implications are -  it means in order to use this facility,
plugins need to be split into GUI and worker threads (plugins can continue
as they are without adverse affect, but with no benefit) where most plugins
today have the worker functions built into the QWidget class.

Anyway, as its hard to explain a look-and-feel with words, I pull some
screenshots into a description here ...

http://www.zen13655.zen.co.uk/mythtv-newmenus.html


I'm looking for comments as to whether this is the right way to do this, and
whether it is aligned with, or clashes with, things like MythUI.  I don't
want to check this in and find it breaks things people are working on; but I
do believe this makes a massive improvement to the user experience.

Paul