feature request: lzma compresion (7zip)

[super master]

Hello,
many linux SW is starting to implement new lzma compresson instrad of old zlib (gzip) od bzip2.

lzma is default comrpession in very good compression SW 7-zip, which is faster and have higher compression ratio then bzip2 or rar.

Currently its probalby the best compressor in therms of compression and decompression speed / compression ratio.

In linux there is GNU lzma SW which implements lzma algorithm.

In my optinion it would be very useful if rsync could use this compressor optionaly as upgrade of old zlib.

more info: http://en.wikipedia.org/wiki/Lempel%E2%80%93Ziv%E2%80%93Markov_chain_algorithm