Refs #2063. Added preparse hook to pipeline.

lib/pipeline/Pipeline.js

@@ -78,6 +78,9 @@ 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.preParse instanceof Function) {
+			pipelineInstance.preparse();
+		}
 
 		/*
 		Wherever there is a match immediately following a sort, swap them.