Preparing for release 1.72.0.
Bumping version
MEncoder: clean up embedded subtitle handling
clean up renderer format matching
@since major.minor -> @since major.minor.revision
cleanup
update update
document and clean up DLNA.ORG_OP flags handling
FFmpeg Video:
    - read custom options before each transcode rather than only at startup
	- rescale videos larger than the renderer's max supported width/height
FFmpeg Video + FFmpeg Web Video:
    - support all TranscodeVideo profiles
    - preserve source video bitrate
FFmpeg Audio: support all TranscodeAudio profiles
PMS.conf: rename ffmpeg -> ffmpeg_video_custom_options and default to null
deprecate unused/obsolete methods, remove unreachable code
CHANGELOG: move misplaced change
fmt + cleanup
flag TODOs
fixup @since major.minor -> @since major.minor.revision
docfix
Protecting access to soapaction, which can be null.
fmt
nitfix
FFmpeg: make bitrate handling reusable
fix NPE in renderer requests for external subtitles
UUID: don't use MAC address seed as it breaks the use of multiple (concurrent) profiles - thanks whickwire