Add jq to docker images.

Add jq to the docker image containing falco. jq is very handy for
transforming json, which comes into play if you want to post to
slack (or other) webhooks.

docker/dev/Dockerfile

@@ -19,6 +19,7 @@ RUN echo "deb http://httpredir.debian.org/debian jessie main" > /etc/apt/sources
  && apt-get install -y --no-install-recommends \
 	bash-completion \
 	curl \
+	jq \
 	gnupg2 \
 	ca-certificates \
 	gcc \

docker/stable/Dockerfile

@@ -19,6 +19,7 @@ RUN echo "deb http://httpredir.debian.org/debian jessie main" > /etc/apt/sources
  && apt-get install -y --no-install-recommends \
 	bash-completion \
 	curl \
+	jq \
 	ca-certificates \
 	gnupg2 \
 	gcc \