Most package installations include compressed source files. This
adds support for common archive types on Windows:
* Add support for using system 7zip functionality to decompress .Z
files when available (and on Windows, use 7zip for .xz archives)
* Default to using built-in Python support for tar/bz2 decompression
(note that Python tar documentation mentions preservation of file
permissions)
* Add tests for decompression support
* Extract logic for handling exploding archives (i.e. compressed
archives that expand to more than one base file) into an
exploding_archive_catch context manager in the filesystem module