[cmake-developers] [OSX CMake.dmg] Replace >10.6 build with 64-bit only and use bzip2 compression

[Adam Strzelecki]

Not an big issue but official DMG bundles are 40 MB where my manually built one is 21 MB (half of it).

So any reason for:
* providing universal FAT binaries instead of 64-bit only for >=10.6 Darwin64 build, as anyway there is 32-bit build for these who have 32-bit only CPU?
* using DMG zlib compression instead bzip2 for all builds which is available for 10.4+ and provides much better compression ratio?

--Adam