avoid creating empty elements
add email task
Don't create a default oozie workflow task. This may be slightly easier
for simple projects, but it can create confusion when one wants to
create multiple workflows in a single gradle project.
Start working towards better DSL support.
Eventually, the goal is to replace the current use of maps to define actions with
typed beans. In the interim, these beans can convert themselves back to maps to support
the WorkflowBuilder engine.
Take this serialization thing seriously