[mythtv] Merging the 'render' branch

[John Pilkington]

On 01/12/2019 11:58, John Pilkington wrote:

> 253d4df44 built and running for el7.  mythtv-setup segfaulted on exit 
> after a no-op visit, and the frontend gave the same 'Widget does not 
> have a window' warning on startup but seems to be running ok.
> 
> Cheers,
> 
> John

And mythpreviewgen trouble again.  None are being autogenerated for SD 
or redio recordings, the only ones created by this box, and running 
mythpreviewgen from the keyboard segfaults after printing the Buzzoff 
protocol version.