change const copy to const reference (cppcheck)
remove unused const copy (cppcheck)

I'm leaving the code there for now as its pulling values from the protocol.
H264Parser::decode_Header: pic_order_present_flag is not required, so don't
insist on it.
DTVRecorder::FindH264Keyframes: Only account for Adaptation Field Control
Offset if payloadStart is set.
Add new columns for Unicable related configuration data

Refs #9726
mythutil - ExtractImage: Always update the image even if one already exists
MainServer::HandleMusicFindAlbumArt: cache any embedded images found
MainServer::HandleMusicTagGetImage: pass the ImageType by number not by name

The imagetype filename is translated which causes problems so safer to just
pass the ImageType value.
AlbumArtImages::scanForImages: fix the image filename

The filename should have been updated to be the myth url of the image.
Partial revert of c64141b0c0b7118ee28be2441374727a1af7c44c

We can use the previous readblocksize as it was adjusted during earlier reads. However we set the initial value in such a way that it will be automatically recalculated on the first call to RingBuffer::CalcReadAheadThresh()
Cache the size of the remote file for 500ms

Aim is to speed up common usage…
Merge remote-tracking branch 'upstream/master'