[mythtv-theming] 'Idle screen' update

[Richard Hulme]

Hi,

As of commit [65279ac4] 
(https://github.com/MythTV/mythtv/commit/6527a9ac4), the idle screen now 
supports showing the current recordings, next recordings and schedule 
conflicts (similar to mythwelcome).

Each of these is a buttonlist, called 'currentrecording', 
'nextrecording' and 'conflicts' respectively.  These widgets are 
optional so you are free to define them or not.

The available attributes in the buttonlist are the same as described here:
http://www.mythtv.org/wiki/Schedule-ui.xml#Generic_Attributes_Used_in_most_windows

The idle screen is described by the window 'standbymode', usually 
defined in status-ui.xml.

I've updated the default and default-wide themes but you may wish to 
override the defaults in your own theme(s).

This change only applies to master.

Richard.