openjdk6: update 1.11 release to 1.11.9
openjdk7: get icedtea version from recipe name like openjdk6
images: add a java test images which includes jre-versions 6 and 7
openjdk6: add latest 1.12 icedtea version
openjdk6: do not unpack some of the downloaded tarballs
README: update about the new versions