1.7in pom

Hi,

two minor changes before the storm :-)

1.) extended gitignore: /target is created by maven, also eclipse specific folders added
2.) Set compiler version to 1.7. If it is not set, a standard value of 1.5 or so is used. In this situation not all of the tests are running and even do not compile. So I assume you also use 1.7. I would suggest: explicitly set the jdk version and test against it, the json-io library requires at least java 1.7. Otherwise we would have to fix the tests and lower the required jdk.