Maven integration + maven-release-plugin/nexus-staging plugins integration

Hallo Andreas,

Hope you are good. 

I've made some changes to the initial project structure and integrated maven-release-plugin.

If you agree with changes could you please do following:

1. Test if Ant build.xml works well for you.
Execute `mvn clean install` in project directory. This will create a `lib` directory with all dependencies. Running `ant` in `build` directory should create all necessary items. I'm not sure if this is compatible with your setup. Please let me know if not.

2. Check if `<keyname>` in pom.xml @ line 159 is correct.

3. Try to make a release as per http://central.sonatype.org/pages/apache-maven.html#performing-a-release-deployment-with-the-maven-release-plugin:

- Run `mvn release:clean release:prepare`. Script will automagically ask about version number, create GIT tag with version.
- Run `mvn release:perform` this will generate all artefacts and sign them with you key. After successful singing it will deploy to central maven repo. 
- After deployment you can release it manually or using nexus-staging plugin `cd target/checkout && mvn nexus-staging:release`

(Optional) Integrate Travis CI by linking server-sass project as per their guide http://docs.travis-ci.com/user/getting-started/. I've already added `.travis.yml` file. 

Thanks,
Anton