Travis CI

Hi!

I've added a Travis CI configuration that automatically builds and tests sbteclipse.
The tests already complete succesfully for my repository: https://travis-ci.org/nightscape/sbteclipse
I've also added a badge which links to the build success of your repository and should become green once you have merged this PR and performed steps 1,2 and 4 from here:
http://about.travis-ci.org/docs/user/getting-started/

I've already filled out the Typesafe CLA so hopefully all is good to go :)

Best
  Martin