Add support for ping.

The emulator needs the ping package from the os in order for ping to
work from adb.

We now install ping to make sure we can ping the outside world.

Fixes #147

Author: Erwin Jansen

emu/templates/Dockerfile.emulator

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     libpulse0 libtinfo5 libx11-6 libxcb1 libxdamage1 \
     libnss3 libxcomposite1 libxcursor1 libxi6 \
     libxext6 libxfixes3 zlib1g libgl1 pulseaudio socat \
+    iputils-ping \
 # Enable turncfg through usage of curl
     curl ca-certificates && \
     apt-get clean && \