Replaced valid_header?() with validate_header(). The new method returns a list of errors instead of just true/false. This allows more descriptive text to be displayed when an invalid file is opened.
Replaced valid_header?() with validate_header(). The new method returns a list of errors instead of just true/false. This allows more descriptive text to be displayed when an invalid file is opened.

lchanmann/wavefile,jstrait/wavefile