Feature/use sbt and bintray for building

improving the build process
* use sbt 0.13
* use sbt-release for releasing
* use sbt-bintray for publishing the artifacts

I know that you would prefer sonatype for publishing but we can start with bintray and see after how to do

What about using the standard src tree ? Would help for contributions

I still need to fix the read me

- [X] propose to add more tests (postpone)
- [X] propose to fix the scaladoc / license display clue (postpone)
- [X] propose to use sbt-ghpages and sbt-sites to build rapture.io (postpone)
- [X] ~~propose to use sbt-ls (postponed due to some problems with the custom directories structures)~~