CB7 libraries for Java

Apache Commons Compress reads and writes 7z in pure Java with SevenZFile and SevenZOutputFile, and handles CBZ and CBT too. Add the org.tukaani:xz dependency: 7z support needs it. Apache-2.0.

• Commons Compress Read and write CB7 (7z) comic book archives in Java with Apache Commons Compress: SevenZFile and SevenZOutputFile, pages in natural order, cover.