Fix - correctly handle LZ4 uncompression
Fix - correctly handle LZ4 uncompression

LZ4 places extra 8 bytes for checksum (ignored in JSROOT).
But when original buffer bigger than 16MB, several independent
compressed buffers created. With LZ4 compression this does not worked
bellenot/jsroot,linev/jsroot,root-project/jsroot,linev/jsroot,bellenot/jsroot,bellenot/jsroot,root-project/jsroot