0.9.0

This release focuses primarily on improving the speed of the decoder.
This is an improvement of between 30-50% in decode time, or 40-80% in throughput.
A lot has changed in certain places.

• Large parts of the block decoder has been rewritten.
• SSSE3 optimized version of the block decoder has been written.
• Accelerated functions that transfer from and to the block decoder has been added, as suggested by Chris.
• Accelerated functions that write to pgm and ppm; the code can be used for other file types, but I was too tired to include this as well. This was suggest by Mike.
• Slightly modified the internal structure of buffers returned when codestream::pull is invoked; this allows buffers from different components to coexist (can be used concurrently). This is needed for the accelerated functions above. Previous designs using this feature should continue working without issues.
• For WASM, we have now accelerated all the decode path including the block decoder using SIMD instructions.
• A bug fix for an issue reported by Pierre, where an empty subband can cause a segmentation fault.
• For windows, added a flag for disable exported functions when static build is used, as suggested by Lucas.
• There might be other issues that I forgot.