Add Pepperflash plugin.

Dockerfile

@@ -1,10 +1,13 @@
 # At some point maybe add variables to control size of screen.
 
-FROM debian:stretch
+FROM debian:buster
 
 COPY waterfox*.tar.bz2 jre-*.tar.gz /root/
 
+RUN sed -i '/ buster main/s/ main/ main contrib non-free/' /etc/apt/sources.list
+
 RUN apt-get --yes update && apt-get --yes install --no-install-recommends \
+    browser-plugin-freshplayer-pepperflash \
     bzip2 \
     fonts-droid-fallback \
     fonts-noto \
@@ -12,11 +15,13 @@ RUN apt-get --yes update && apt-get --yes install --no-install-recommends \
     libasound2 \
     libdbus-glib-1-2 \
     libgtk-3-0 \
+    pepperflashplugin-nonfree \
     ratpoison \
     tightvncserver \
     xfonts-base \
     x11-xserver-utils \
-    xterm
+    xterm \
+    zile
 
 RUN set -x; \
     mkdir -p /usr/local/java && \

README.md

@@ -15,11 +15,6 @@ See `create.sh` and `run.sh` for ways one might use the image.
 Something along the lines of the `run.sh` formulation might work well
 as the command portion of a tunneling `ssh -L 5900:127.0.0.1:5900` command.
 
-This version is based on Ubuntu rather than Debian, because I was
-trying to get the icedtea-web Java Plugin stuff to work.  Didn't work,
-but then I tried a recipe for getting Java SE instead of OpenJDK, and
-that does seem to work.  Might work equally well on Debian.
-
 Sadly, this approach requires one to download JRE directly from
 Oracle, get an account, and check through a license agreement, so I
 can't just give it away, you'll have to download the JRE yourself.
@@ -48,7 +43,5 @@ The hack for preconfiguring Waterfox's MIME handler to run
 `/usr/bin/javaws` for `jnlp` files is particularly disgusting, but
 none of the rest of this is particularly nice either.  Whatever.
 
-If you really need Flash for something on top of all this insanity,
-the path that works with Waterfox appears to be
-
-<https://wiki.debian.org/PepperFlashPlayer/Installing>
+This version is based on Debian Buster, so that we can use
+`PepperFlashPlayer` via an APT package.