* move compression header to compression.h
* prototype with zstd compression
* updated capabilities
* no need for resetting compression
* left-over reset function
* use ZSTD_compressStream() instead of ZSTD_compressStream2() for backwards compatibility
* remove call to LZ4_decoderRingBufferSize()
* debug signature failures
* fix the buffers of lz4
* fix decoding of zstd
* detect compression based on initialization; prefer ZSTD over LZ4
* allow both lz4 and zstd
* initialize zstd streams
* define missing ZSTD_CLEVEL_DEFAULT
* log zero compressed size
* debug log
* flush compression buffer
* add sender compression statistics
* removed debugging messages
* do not fail if zstd is not available
* cleanup and buildinfo
* fix max message size, use zstd level 1, add compressio ratio reporting
* use compression level 1
* fix ratio title
* better compression error logs
* for backwards compatibility use buffers of COMPRESSION_MAX_CHUNK
* switch to default compression level
* additional streaming error conditions detection
* do not expose compression stats when compression is not enabled
* test for the right lz4 functions
* moved lz4 and zstd to their own files
* add gzip streaming compression
* gzip error handling
* added unittest for streaming compression
* eliminate a copy of the uncompressed data during zstd compression
* eliminate not needed zstd allocations
* cleanup
* decode gzip with Z_SYNC_FLUSH
* set the decoding gzip algorithm
* user configuration for compression levels and compression algorithms order
* fix exclusion of not preferred compressions
* remove now obsolete compression define, since gzip is always available
* rename compression algorithms order in stream.conf
* move common checks in compression.c
* cleanup
* backwards compatible error checking
