Added retina display support

Fix arduino/Arduino#2309

Author: cmaglie

appbundler/src/com/oracle/appbundler/AppBundlerTask.java

@@ -472,6 +472,7 @@ private void writeInfoPlist(File file) throws IOException {
             writeProperty(xout, "CFBundleSignature", signature);
             writeProperty(xout, "CFBundleVersion", version);
             writeProperty(xout, "NSHumanReadableCopyright", copyright);
+            writeProperty(xout, "NSHighResolutionCapable", "true");
 
             if (applicationCategory != null) {
                 writeProperty(xout, "LSApplicationCategoryType", applicationCategory);