Upgrade to 8.2

[drwilco]

I used your repo to help me add NetBeans to an existing image, for which my thanks!

However, a quick note if you're going to update this to 8.2, I discovered that --silent hangs after a while when run by docker. I figured out that adding DISPLAY=:0 to the environment fixes it:

RUN DISPLAY=:0 /tmp/netbeans-8.2-cpp-linux-x64.sh --silent --userdir /tmp/nbi

I don't use --state, as the default is fine for me.