Use New Relic Maven repository to include newrelic-api.jar

Hi,
I think it would be better to fetch the newrelic-api.jar via Maven.
I asked the New Relic support for their public Maven repository and used the information they gave me to update my fork. It now uses the latest 2.9.0 release of the New Relic API.

I also added a basic gitignore to the project so it might work better with IDEs like GGTS etc.

Do you have any additions?

Thanks,
Mat