* Fixes a bug in the test function where sample sizes would not be
doubled, resulting in format identification failure.
* Fixes a bug in the test function where -1 would be returned
unconditionally, resulting in format identification failure.
* Fixes a bug in the depack function where sample sizes would not
be doubled, resulting in garbage pattern data being loaded.
* Normalized header depacking to not require seeks in the output
file (to match the other ProWizard loaders).
