remove vtkTemporalDataSet and push its pipeline support to filters

The main change is to remove the use of vtkTemporalDataSet and move
the support of multiple temporal data sets from the execution
pipeline to filters. To be specific,

- Before, a filter can request objects from multiple time steps by
  setting the key UPDATE_TIME_STEPS to a vector of doubles; the
  resulting objects get wrapped by the pipeline into a single
  vtkTemporalDataSet object.

- After, a filter can only ask for a single time step from the
  pipeline by setting the key UPDATE_TIME_STEP to a single double.
  The "wrapping" no longer happens. If a filter want to request
  multiple time steps, it needs to either inherit from
  vtkMultiTimeStepAlgorithm or use the CONTINUE_EXECUTION to loop the
  upstream pipeline and store the data from each iteration.

The following key changes/constants are backward incompatible:

vtkStreamingDemandDrivenPipeline::UPDATE_TIME_STEPS(() ->
   vtkStreamingDemandDrivenPipeline::UPDATE_TIME_STEP((),
   vtkMultiStepAlgorithm::UPATE_TIME_STEPS()

vtkStreamingDemandDrivenPipeline::PREVIOUS_UPDATE_TIME_STEPS() ->
  vtkStreamingDemandDrivenPipeline::PREVIOUS_UPDATE_TIME_STEP()

deleted: vtkCompositeDataPipeline::REQUIRES_TIME_DOWNSTREAM()

depreicated: VTK_TIME_EXTENT

Change-Id: I635b6401ae4f0a7ea7c4b5c466ced40ee75963c7