Add support for downloading OSX JDKs 1.6 and older only available from Apple

[jvanzyl]

No description provided.

[atanasenko]

There is a osx jdk1.6 image available at http://support.apple.com/downloads/DL1572/en_US/javaforosx.dmg.
The packaging format is the same, though the contents differ. One main difference is that the content really wants to be under the root of the filesystem:

JavaForOSX.pkg

/Library/Java/JavaVirtualMachines/1.6.0.jdk/

JavaEssentials.pkg

/System/Library/Java/Extensions/*
/System/Library/CoreServices/Jar Launcher.app/*
/System/Library/CoreServices/Java Web Start.app/*
/System/Library/Frameworks/JavaFrameEmbedding.framework/*
/System/Library/Frameworks/JavaVM.framework/*
/System/Library/PrivateFrameworks/JavaApplicationLauncher.framework/*
/System/Library/PrivateFrameworks/JavaLaunching.framework/*
/System/Library/Java/Support/CoreDeploy.bundle/*
/System/Library/Java/Support/Deploy.bundle/*
/usr/bin/
/usr/libexec/
/usr/share/man/

JavaMDNS.pkg

/System/Library/Java/Extensions/dns_sd.jar
/usr/lib/java/libjdns_sd.jnilib

[atanasenko]

The most important of those seem to be /System/Library/Frameworks/JavaVM.framework and /Library/Java/JavaVirtualMachines/1.6.0.jdk/, they contain a number of symlinks to each other and there are two sets of binary executables with different sizes. I'm not sure if it possible to merge this stuff together somehow and I cannot check it since I have no mac.