ignore private directory

projects/MulticastExample/MulticastSenderExample/nbproject/private/private.xml

-<?xml version="1.0" encoding="UTF-8"?>
-<project-private xmlns="http://www.netbeans.org/ns/project-private/1">
-    <editor-bookmarks xmlns="http://www.netbeans.org/ns/editor-bookmarks/2" lastBookmarkId="0"/>
-    <open-files xmlns="http://www.netbeans.org/ns/projectui-open-files/2">
-        <group>
-            <file>file:/Users/mcgredo/projects/gitlab/NetworkedGraphicsMV3500/projects/multicastExample1/MulticastSenderExample/src/multicastsenderexample/MulticastSenderExample.java</file>
-        </group>
-    </open-files>
-</project-private>
+<?xml version="1.0" encoding="UTF-8"?>
+<project-private xmlns="http://www.netbeans.org/ns/project-private/1">
+    <editor-bookmarks xmlns="http://www.netbeans.org/ns/editor-bookmarks/2" lastBookmarkId="0"/>
+    <open-files xmlns="http://www.netbeans.org/ns/projectui-open-files/2">
+        <group>
+            <file>file:/Users/mcgredo/projects/gitlab/NetworkedGraphicsMV3500/projects/multicastExample1/MulticastSenderExample/src/multicastsenderexample/MulticastSenderExample.java</file>
+        </group>
+    </open-files>
+</project-private>