DVB: Support EPG information for FreeView broadcast (UK DVB-T2).

This ticket fixes #3179.
DVB EPG: Show the parental rating when available.
DVB EPG: Show the content type when available.
Disable "File > Subtitle Database > Download" in capture mode.
Subtitle downloader: Remove the extra comma after the movie title.
VMR9/EVR renderers: Fix high CPU and memory usage when switching the user account.

This commit fixes #3176.