specification. Simplify things by removing most of the
support for known uncompressed size in most places.
There are some miscellaneous changes here and there too.
The API of liblzma has got many changes and still some
more will be done soon. While most of the code has been
updated, some things are not fixed (the command line tool
will choke with invalid filter chain, if nothing else).
Subblock filter is somewhat broken for now. It will be
updated once the encoded format of the Subblock filter
has been decided.
liblzma as easy as using zlib, because the easy API
don't require developers to know any fancy LZMA options.
Note that Multi-Block Stream encoding is currently broken.
The easy API should be OK, the bug(s) are elsewhere.
