Fix the wavedecoder a little.

Fix the wavedecoder a little.

Handle RIFX and corrupted files better.  Update the autotest so that it
is run properly (and copies files properly in shadow build).  Fix the
gendata script to properly create testdata.

Change-Id: I47b705507bebaef54df2835ec767c6b220c64678
Reviewed-on: http://codereview.qt-project.org/6380
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: derick hawcroft <derick.hawcroft@nokia.com>