Major changes, including Brotli and Lizard

- update of zstd-mt library
- add brotli v0.6.0
- add lizard v2.0
- xxhash is from zstd for lz4, lz5 and lizard now
- update also the documentation, where needed

C/brotli/enc/histogram.h

@@ -12,7 +12,7 @@
 #include <string.h>  /* memset */
 
 #include "../common/constants.h"
-#include <brotli/types.h>
+#include "../types.h"
 #include "./block_splitter.h"
 #include "./command.h"
 #include "./context.h"