Installer: Use lzma2/ultra for compression
 - Thanks to this we're able to remove 1.92 MB (2018268 bytes) from installer
 - Note: this way memory usage is increased from from 95MB to 372MB
 http://www.jrsoftware.org/ishelp/index.php?topic=setup_compression
Merge pull request #134 from vBm/master

Installer: Use lzma2/ultra for compression