Add primitives to the workflow scratchpad

You can add any primitive value to the scratchpad.

     // numbers
     workflow.scratchpad.maxdays = 100;
     workflow.scratchpad.pi      = 3.14159267;
 
     // booleans
     workflow.scratchpad.canSave   = true;
     workflow.scratchpad.isHoliday = isHoliday( new Date() );
 
     // string
     workflow.scratchpad.next_holiday = 'Christmas';