adding dockerfile, versions file and build script

- creating basic java base image
- adding build script
- adding gitignore
- adding dockerfile
- installing oracle java 7, oracle java8, openjdk 6, openjdk7
- setting oracle java 7 as default
We need to follow the same convention as the other dockerfiles -- one package per line and in alphabetical order. Also, I'm not sure what `-yy` accomplishes. Will `-y` not do in this case?