v20.0.0

This release features the following improvements to decompression :

1. large speed improvement for tiled images, particularly for those with TLM markers
2. support for true progressive decompression by layer - no duplicate decompression of overlapping layers
3. support for asynchronous decompression: client can efficiently wait for a particular tile or for the entire image to be decompressed.
4. improved Python bindings and viewer
5. efficient decompression over network using libcurl, with support for S3 and MinIO storage. Speed of network decompression can rival local file decompression, depending on network latency.
6. integration with GDAL through downstream JP2Grok driver
7. many bug fixes

The core_decompress example demonstrates how many of these new features are used.