Refs #2063. Removed preprocess hook.

lib/pipeline/Pipeline.js

@@ -79,9 +79,6 @@ var Pipeline = module.exports = (function(){
 		/* Move filters up where possible.
 		CW TODO -- move filter past projections where possible, and noting corresponding field renaming.
 		*/
-		if (pipelineInstance.preProcess instanceof Function) {
-			pipelineInstance.preProcess();
-		}
 
 		/*
 		Wherever there is a match immediately following a sort, swap them.