Extra bits on the sequence stream are ignored

[klauspost]

It seems that any leftover bits on the sequence stream are ignored.

While it is debatable what it should do, it should either:

1. Cause an error or
2. Be specified in the spec

Here are a couple of samples with extra bits in the sequences:

extrabits.zip

[Cyan4973]

That's a good point @klauspost ,
the decoder must consume exactly all bits, and not more.
If some bits remain, it should be considered an error.
Something to clarify, and enforce.

[terrelln]

The patch now errors when it detects the bitstream isn't complete. This flags the error on all the inputs in extrabits except 0ef619d15539778c4ba2ec7fc51d526226a5b816. That input "overflows" the bitstream and returns BIT_DStream_overflow. The overflowed data is ignored.