JxBrowser binaries are too large to store in the git repo.

[chrisdembia]

remote: warning: GH001: Large files detected. You may want to try Git Large File Storage - https://git-lfs.github.com.
remote: warning: See http://git.io/iEPt8g for more information.
remote: warning: File jxbrowser/release/modules/ext/jxbrowser-mac-6.14.2.jar is 50.27 MB; this is largerthan GitHub's recommended maximum file size of 50.00 MB
To https://github.com/opensim-org/opensim-visualizer
   6fdc50c..3caa410  opensim-gui -> opensim-gui

We could use Ant or CMake to download the jxbrowser binaries.