Add support for bz2/bzip2 files

[PHPirates]

Please add a list to readme with supported file types, so I could have seen immediately whether I can use this library or not.

ERROR - rains.concurrency.AsyncPromise - Unknown compression type bz2 
java.lang.IllegalArgumentException: Unknown compression type bz2
	at org.rauschig.jarchivelib.ArchiverFactory.createArchiver(ArchiverFactory.java:83)

Using version 1.1.0

Apache supports them: http://commons.apache.org/proper/commons-compress/examples.html

You might also want to keep your website up to date w.r.t version: https://rauschig.org/jarchivelib/download.html

[thrau]

Yep, it's on my list ;-) Thanks for the nudge though.