Minor refactorings in PortBindingParser related code
Use docker-java 0.10.3-SNAPSHOT

Since 0.10.2, DockerClientBuilder ignores empty version strings, so
there is no more need to handle this case here.
Another change is that docker-java now uses ServiceLoader internally to
locate its implementation, which fails with the default classloader.
Parser for Bind definitions
Parse multiline definitions
javadoc BindParser