vis.js: enable middle mouse button
emulate default middle mouse button behaviour by opening new tab when clicked
Signed-off-by: Juha-Pekka Heikkila juhapekka.heikkila@gmail.com
emulate default middle mouse button behaviour by opening new tab when clicked
Signed-off-by: Juha-Pekka Heikkila juhapekka.heikkila@gmail.com