output/analog: Fix channel deinterleaving.
output/wav: Fix channel deinterleaving.
input/wav: Deal with IEEE float samples in WAV files.

This also skips chunks before the 'data' chunk in WAV files, as
this is quite common.
input/csv: Match format on .csv extension in filename.
input/vcd: Make less noise in format match failure.
Doxygen: Update paths.