 Version 6.13.6

* created a fast update routine to improve performance
	* all updates (swipe or scheduled etc) run the fast update routine
	* full update (for which I don't see the reason) can be run from the menu of Subscriptions view
* the full update routine is also enhanced for performance
* enhanced youtube update routines to include infinite new episodes updates
* added update routine for youtube channel tabs
* added audio and video quality settings in Feed Preferences (Youtube feeds only): Global, Low, Medium, High
	* these settings take precedence over global situations
	* when Global is set, video is a lowest quality, and audio is at highest quality (except when prefLowQualityMedia is set for metered networks)
* fixed mis-behavior of multi-selection filters
