Checks that there's enough input to packDar.
Specific function to calculate offsets for the index.
putINDEXheader function uses the index calculator and putINDEXNode takes a IndexNode as input.
packDar should now use a constant amount of memory when packing DAR files.
It reads and writes the files that are to be DataNodes one by one. The lookup function is broken as the index calculator for the offsets of DataNodes doesn't a count for the 4 + 8 + nodeLen bytes at the start of each DataNode.