add yuv444p, yuv422p, and yuv420p output format (lower cpu usage
on ffplay playback because it does not do format conversion)
custom size with size/s option (fullhd option is deprecated)
custom layout with bar_h, axis_h, and sono_h option
support rational frame rate (within fps/r/rate option)
relaxed frame rate restriction (support fractional sample step)
support all input sample rates
separate sonogram and bargraph volume (with volume/sono_v and
volume2/bar_v)
timeclamp option alias (timeclamp/tc)
fcount option
gamma option alias (gamma/sono_g and gamma2/bar_g)
support custom frequency range (basefreq and endfreq)
support drawing axis using external image file (axisfile option)
alias for disabling drawing to axis (text/axis)
possibility to optimize it using arch specific asm code
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>