Zip recompression doesn't work when archive is not compressed

[andrews05]

For zip archives that have been created using level 0 ("store"), ect does not recompress the files inside.

[andrews05]

Found this is deliberate by Leanify, though not sure why.
For the record, advzip happily compresses these files.

[fhanau]

https://github.com/fhanau/Efficient-Compression-Tool/blob/master/src/leanify/zip.cpp#L330
According to source code, this may break files. Even though I did not verify this claim, I don't think it's worth risking it.

[fhanau]

Ok, according to JayXon/Leanify#42 this seems to be fine in most cases, so I will at least port these changes to add an option to compress uncompressed files within a zip file.