Allow SDE users to set the query order with a PROCESSING switch

[hobu]

In certain cases, you will want to have SDE *not* query against the spatial
index if you have a FILTER in place.  

PROCESSING "QUERYORDER=ATTRIBUTE"  on the SDE layer in question should do the trick.

[hobu]

  proc_value = msLayerGetProcessingKey(layer,"QUERYORDER");
  if(!proc_value) {
      query_order= 2; /* SE_SPATIAL_FIRST */
  }
  else if (proc_value=="ATTRIBUTE"){
      query_order = 1; /* SE_ATTRIBUTE_FIRST */
  }
    
  
  status = SE_stream_set_spatial_constraints( sde->stream, 
                                              query_order, 
                                              FALSE, 
                                              1, 
                                              &constraint);

[hobu]

added to 4.9