add references: JAR and X3D-Edit

README.md

@@ -6,9 +6,11 @@ Key course sites:
 
 References and Resources:
 * [GitLab Flavored Markdown (GFM)](https://docs.gitlab.com/ee/user/markdown.html)
+* [Java Archive (.jar)](https://docs.oracle.com/javase/tutorial/deployment/jar/basicsindex.html) for sharable/runnable software libraries
 * [Java SE JDK 8 download](http://www.oracle.com/technetwork/java/javase/downloads/index.html) (not JDK 9)
 * [Netbeans 8.2](http://www.netbeans.org) and [Using Git Support in NetBeans IDE](https://netbeans.org/kb/docs/ide/git.html) 
 and [Video of Cloning a Git Repository Using NetBeans IDE](https://netbeans.org/kb/docs/ide/git_nb_ssh_screencast.html)
 * [Open-DIS Repository](https://github.com/open-dis) and [Distributed Interactive Simulation: The Missing Handbook](https://github.com/open-dis/DISTutorial/blob/master/README.md)
 * [Savage Developers Guide](https://savage.nps.edu/Savage/developers.html) resources for [DIS](https://savage.nps.edu/Savage/developers.html#DIS)
 * [WireShark](https://wireshark.org) and [WireShark Tutorial for Beginners](https://www.youtube.com/watch?v=TkCSr30UojM) video by Anson Alexander
+* [X3D-Edit](https://savage.nps.edu/X3D-Edit/#Downloads) as Netbeans Plugin