oggenc --ignorelength is not implemented

vorbis-tools 1.4.0

--ignorelength switch is documented in --help, and is being passed to format loaders, but is not used anywhere.

problems:

1. if the wavelength is non-zero, it will not be ignored by --ignorelength switch

2. if wavelength is zero, it will be ignored, and entire wave file will be processed, no matter if --ignorelength switch is used or not.