Fix Math.atan2: Swap x and y components.

Author: mathieuouillon

reconstruction/alert/src/main/java/org/jlab/rec/ahdc/Track/Track.java

@@ -48,7 +48,7 @@ public Track(ArrayList<Hit> hitslist) {
 	double p = 150.0;//MeV/c
 	//take first hit.
 	Hit hit = hitslist.get(0);
-	double phi          = Math.atan2(hit.getX(), hit.getY());
+	double phi          = Math.atan2(hit.getY(), hit.getX());
 	//hitslist.
 	this.px0  = p*Math.sin(phi);
 	this.py0  = p*Math.cos(phi);