Travis-CI support

_Running tests automatically on Travis-CI._
This is a good thing.
It works (see build on travis: https://travis-ci.org/sajmoon/Resteasy/builds/30548545) but it takes a while. There is one retry in the build process after failing async build once. I don't know why.

_The .travis.yml contains:_
- Install JCE.
- Add MAVEN_OPTS to travis config.

Also added a Dockerfile. This could definitely be removed, however I used it as a "test environment" to see how to setup dependencies. (mavenopts, JCE etc).

_Setup_
If this gets merged you need to set up Travis so it builds all branches and interacts with github with feedback.