* Back commonPipelineEnvironment step by shared class
Each pipeline step comes with its own instance of a commonPipelineEnvironment.
Properties stored on one instance was not shared with the other instances.
Now we strip down the commonPipelineEnvironment step and forward basically
everything to a shared singleton instance.
With that approach all instances of commonPipelineEnvironment shares the
same data and can now be really used for information exchange between the steps.
Before that change only the commonPipelineEnvironment instance associated with
the pipeline script itself could be used for that purpose.
* Remove unneeded commented line
