New function to efficiently remove the last entries from an archive

[depth42]

Changes proposed in this PR

In this pull request, I added a new function for incrementally removing the last entries from an archive. This is very handy, when you want to remove and re-add entries add the end of an archive as you don't have to rewrite the archive in full.
The function is: Archive.removeAllEntries(fromEntry entry: Entry)

Tests performed

I implemented trhee tests for the function following the existing test pattern.

• testRemoveFromEntryUncompressed
• testRemoveFromEntryCompressed
• testRemoveEntriesFromArchiveWithZIP64EOCD

[weichsel]

Thanks for providing this PR. I like the idea of using truncate as fast-path when possible but I wonder if it wouldn't be better to keep that an implementation detail.
We could check wether the entry to remove is the last one and use the code in the PR as alternate but private code path. (and provide a generic remove multiple entries at once API as follow-up)

[depth42]

It took a while, but I've implemented your suggestion in the pull request: I've added a function for removing multiple entries from an archive (this fixes #109), with a fast-path for truncation if the entries to remove are contiguous at the end of the archive.