Add function to install Oracle Java instead of OpenJDK

I used help from:
- http://www.webupd8.org/2012/01/install-oracle-java-jdk-7-in-ubuntu-via.html
- http://www.webupd8.org/2012/06/how-to-install-oracle-java-7-in-debian.html
- https://launchpad.net/~webupd8team/+archive/java

I hope the script helps to create the Oracle Java installation function on the TODO list ;-)
And I hope that there are not so many issues in my script.