Improve TsMuxer channel name grabbing.
Use the designation code to figure out the teletext format, and make the most of the available information.
With mag 8 packet 30 format 1 and 2 we can use the country and network identifiers with a dictionary of registered identifiers to figure out the channel name.
Also, be more careful to check the validity of the data. We have Hamming codes and parity checks to help us with this... so let's use them!
Add pin lock to fix deadlock when attempting to stop and start the filter quickly (CanDeliver() held receive lock and tried to acquire filter lock while Stop() held filter lock and tried to acquire receive lock).
Don't update the SDT on detection of service type change in PMT update unless the SDT is being delivered. Avoids premature injection of SDT with missing channel name.