Modification to enable producing consistent binary output for the same data

[ziembla]

Three elements were needed:

• modification timestamps for files being zipped have to be set explicitly to 1980-01-01 (as MS Word does) not defaulting to current time,
• relationship infos have to be sorted to make xml stable,
• docx parts have to be sorted to make file order in zip stable

For my documents that's all that was needed to keep binary output stable. I hope it helps!