parameter from scheduler.xml should be available as environment variables in shell jobs

similiar to the job and order parameter the parameters set in scheduler.xml should be available in shell jobs.

Workaraounds:
1. Define the necessary Variables in your OS environment
2. insert a pre processing step in your job to transfer the parameters from scheduler.xml as order/task parameters:

function spooler_task_before() {
	spooler_task.params.merge( spooler.variables );
	return true;
}