The previous commit was broken.  D'oh!

The IsActive() method returned true even if the timer was not active,
after it completed once.  This broke the state file timer, and the
state file was not saved periodically.

Check for STOP before decoding the first chunk.  This reduces the
command latency.

Remember the chunk's total size.

Nobody cares.

Eliminate the loop from dsdiff_stream_decode().  It makes the code
complex, real-world files with multiple DSD chunks are outside of the
specification, and the "chunk_size" variable would be bogus anyway.

Unused.  Bit reversing is done in the decoder.

Obtained from the Mercurial repository at
https://code.google.com/p/dsd2pcm/

Check for STOP before decoding the first chunk.  This reduces the
command latency.

This allows the compiler to discard buffer contents between two
iterations.

Nobody cares.

Prepare refactoring the whole plugin to use blocks instead of bytes.
A block is the smallest addressable unit, and it will simplify the
seeking code.

This finishes the multi-channel support.  Development of the feature
was started with commit 02cc77cd

When calculating the upper bound using the "sample count" format
header, don't assume it's stereo.

The plugin was horribly bugged for files that were not stereo.

Don't pass the buffer size to the function, as it's known at compile
time.  Use "restrict" on the pointer arguments, and merge the two
loops, which allows the compiler to optimize this loop with a few SSE2
instructions.

Read one block at a time.  This discards the last partial block, which
cannot be interleaved anyway.  Previously, uninitialised memory was
used to interleave the last block, which generated some noise.

Convert into a second buffer that gets passed to decoder_data()
without copying back to the first buffer.

This allows the compiler to discard buffer contents between two
function calls.

Same bug as in the previous commit.

When the data chunk size is not a multiple of the frame size, the last
partial frame lead to an endless loop.  We fix this by checking
chunk_sze>=frame instead of chunk_sze>0.  This way, the partial frame
is simply skipped.