add timing functions
synchronised playback
add delay reporting to sinks
add support for generic sinks
support for mach time
remove unused funtions
alllow record without rtp-info
set loose rtp mode if record does not have RTP-info
fix lock in buffer_get_frame
Merge branch 'sntp' of https://github.com/Nachtzuster/shairport into sntp

Conflicts:
	audio_alsa.c
	common.h
	player.c
	rtp.c
	rtsp.c
	shairport.c