Simplify internals and rewrite file header parsing code:

Simplify internals and rewrite file header parsing code:
- remove -M, -t, -w, -C, -x flags that don't make sense anymore
- make "-j off" the default (sndiod already does the job)
- don't limit the number of played/recorded files.
- add support for floating-point encoded files.
- add support for apple .aiff and sun/next .au files