Rewrite IntBTree to use multi value nodes (typically 16 values). Add missing clear() in test code
Port Yuta Mori's DivSufSort to Java. Extract SA_IS from the BWT and move it to
the util package. Replace SA_IS with DivSufSort as default implementation of
suffix array creation algorithm in the BWT forward method.
It yields a typical performance boost of 10-15% when encoding using the Block or
BWT transform.
Add length validation during decoding
Fix a bug that would cause the program to hang for block sizes over 16 MB.
A change in the block header encoding requires a bitstream version update.
Remove unnecessary flush()/Sync() call that impacted write performance (especially for Go).
Save prediction state in a field. Initialize with default value.
Get() becomes a simple accessor.
A few minor simplifications/updates/optimizations.