BZIP2 compression. Looks like a fork from Apache CBZip2InputStream, with minimal code (eg decode only)

@see "https://svn.apache.org/repos/asf/ant/core/trunk/src/main/org/apache/tools/bzip2/"

@see "https://code.google.com/p/jbzip2/"

@see "http://en.wikipedia.org/wiki/Bzip"