fix a problem where the input and output ports were being deleted too early. We want to delete the connections but leave the arrays

ENH: Updated vtkTableExtentTranslator to support providing a different number of extents than are in the table.  Currently this may not work well when the number of pieces requested is greater than one but less than the number of pieces in the table.  Not all data will be returned in this case.

BUG: Fixed order of operations for breaking a data object away from its producer and connecting it to another pipeline.  Needed to work with executive-based pipelines.

ENH: Moved ghost level array generation in structured output from duplicated UpdateData methods in the structured data objects to a single GenerateGhostLevelArray method in vtkDataSet.  This is now possible because the extent is stored in the information object on each data object.  This code is now called by vtkSource at the end of UpdateData.  Similarly the call to Crop() was moved from vtkDataObject::UpdateData to the end of vtkSource::UpdateData.