AE: accept planar formats and pts from player

ActiveAE now supports planar audio formats at input. Decoded planar audio from .i.e. dts or dd can go all the way through AE to the sink. In particular interesting for Pi , @popcornmix

Simplify dvdplayer's interface to AE. Drop obsolete conversion to interleaved in ffmpeg audio codec. Pass pts to AE instead of guessing playing pts by error prone calculation using delay.
Drop obsolete leftover buffer, we only get entire frames from the codecs.

Drop obsolete pcm audio codecs. lpcm wasn't used anyway. Nothing which can't be done by ffmpeg.

Adjust paplayer to interface changes.

@elupus I have based this on masterclock for testing. 
Hmm, I'm not aware of any difference between LPCM and PCM above 16bits... (actually LPCM is a subset of PCM, but in practice "PCM" always refers to "LPCM" instead of the other technically PCM encodings such as ADPCM / A-law / µ-law).

Looking at the removed "LPCM" decoder, it looks like it decodes some PCM format that has regular 16bit samples, plus after every 4th sample there is an additional 4 bytes, each of which can be added as an additional LSB byte to the preceding 4 regular samples, producing 24bit samples. So it is a weird PCM format, but the name "LPCM" seems to be a misnomer as it is more than just simple PCM/LPCM.

Looking at the history of the decoder, I don't understand how it was ever plugged into anything, since it had custom codec IDs that seemingly were never referred to from outside the codec... I guess some weird xbox-era magic I know nothing about may have caused it to be used.

Taking a look the audio decoders FFmpeg has, it seems this audio format is known there as "pcm_dvd" aka AV_CODEC_ID_PCM_DVD ("PCM signed 16|20|24-bit big-endian for DVD media"), and is handled properly.