Minor tweaks

- specified the webpage where to look for info when user has to problems with Java 7 version
- specified license after checking [licence of Arduino 1.5 for Java 7](https://github.com/arduino/Arduino/blob/ide-1.5.x-java7/license.txt) and [licence of Arduino 1.5 for Java 6](https://github.com/arduino/Arduino/blob/ide-1.5.x/license.txt)