Update the README and license after discovering source of decompression code.

Stumbled across http://code.google.com/p/js-lzma/ and realized it was
identical to the source code for the decompressor I got from upstream.
Update to latest code from http://code.google.com/p/js-lzma upstream.
Add test case showing that we can decompress standard .lzma-format files.

The test cases are borrowed from the bzip2 source code.
Notes on the lzma file format and interoperability.
Renamed package to distinguish it from the other js implementation of lzma.