Single file zip decompresion

Apple convert single files to .zip when running "Compress this file", and would be good to be able to unzip the file.  .unzip() isn't for this case.   For example, Perfetto only has gzip support.  I have C++ code to handle this, but was just missing this omission in this otherwise amazing library.

I ended up renaming .zip()/.unzip() -> .zlib()/unzlib() in my local copy.