Renamed build_openjdk_images to build_openjdk_clean_images for the 2nd execute block for openjdk8 recipe.
Swapped order of execution of code blocks build_openjdk_clean_images and ...build_openjdk_images.
Replaced [build_folder] with [build_log_file] to resolve selecting the correct build process.
Merged master changes into branch.
Update README.md
Added environment variables to save JAVA_HOME settings for jdk8 and jdk9.