- added a spectrum analyser
  options are:
	-nb :  number of bands , 20 or 80 (80 is default)
	-separ : how many blank pixels between bands (1 default)
	-amp : vertical amplification ( 3 default)
	-peaks: draw peaks ? (default 1)

  - improved options parsing

* fft.c, fft.h :
	FFT code mainly taken from XMMS (adapted coding style)

* visual.c:
	Sanity checks (users aren't stupid, are they ? )

* LIST: updated the list