Modified implementation of com.sun.nio.zipfs.ZipFileSystem that allows to:
read index (central directory), modify it and write at specified offset.
The changes focus on making public whatever is required and remove what is not.
It is possible to use unmodified ZipFileSystem to implement operations required
for Straight to Jar but it does not work in place (has to recreate zips) and does
not allow to disable compression that makes it not efficient enough.