Add triangle and filled triangle marker shape

Author: elevans

src/main/java/org/scijava/plot/MarkerStyle.java

@@ -35,5 +35,14 @@
  * @author Matthias Arzt
  */
 publicenumMarkerStyle{
-NONE, PLUS, X, STAR, SQUARE, FILLEDSQUARE, CIRCLE, FILLEDCIRCLE
+NONE,
+PLUS,
+X,
+STAR,
+SQUARE,
+FILLEDSQUARE,
+CIRCLE,
+FILLEDCIRCLE,
+TRIANGLE,
+FILLEDTRIANGLE,
 }