Layer-1 support not heavily tested .. 
I-stereo in Level-3 seems to work now, but I have to optimize it.
general optimizations in Level-3 code.
add CRC check.
no 'free format stream' support.
in layer2.c:
	step_two: fraction as pointer .. 
	process first channel 0 than channel 1
	copy channel 0 to channel 1 for: i >= jsbound

- better frame reader .. especially for layer 3 
- MPEG system stream decoder
- check again layer1 !!
- Write a special (optimized) 'single channel' decode.
- optimized dct64 for down sampling modes
- native audio support for AIX and DEC
- update manpage
- optimizations for downsampling modes on layer2 and layer1

