support processing bzip compressed files

[jtmoon79]

Support processing .bz and .bz2 files; both compressed by bzip2.

Such compression is rarely used for log files common on Mac OS and other BSD.

The good news: IIUC, bzip only compresses one file to one compressed file.
From Wikipedia

It is not an archiver like tar or ZIP; the program itself has no facilities for multiple files, encryption or archive-splitting

Hopefully this "one file to one file" compression means bzip is easier than gz and xz support in that there is no need for hacks to handle/workaround "multiple streams" (see Issue #11 , Issue #8 ).

Rust crates available:

• bzip2_rs
  bzip2_rs is a pure Rust bzip2 decoder.
• bzip2
  This library contains bindings to libbz2 to support bzip compression and decompression for Rust.
• bzip2_sys
  Does not look ready for consumption.