Use svagi/phantomjs debian image

- enables faster builds
- prevents phantomjs rate limit (see ariya/phantomjs#13953)

api/Dockerfile

@@ -1,16 +1,13 @@
-FROM debian:jessie
+FROM svagi/phantomjs
 MAINTAINER Jan Svager <[email protected]>
 ENV DEBIAN_FRONTEND='noninteractive' \
   NODE_VERSION='5.7.0' \
-  PHANTOM_VERSION='2.1.1' \
-  INSTALL_DEPS='wget xz-utils bzip2' \
-  RUNTIME_DEPS='ca-certificates fontconfig'
+  INSTALL_DEPS='wget xz-utils' \
+  RUNTIME_DEPS='ca-certificates'
 RUN apt-get update \
  && apt-get install --no-install-recommends -y $INSTALL_DEPS $RUNTIME_DEPS \
  && wget -qO- https://nodejs.org/dist/v$NODE_VERSION/node-v$NODE_VERSION-linux-x64.tar.xz \
   | tar -xJ -C /usr/local --strip-components=1 \
- && wget -qO- https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-$PHANTOM_VERSION-linux-x86_64.tar.bz2 \
-  | tar -xj -C /usr/local --strip-components=1 \
  && apt-get purge --auto-remove -y $INSTALL_DEPS \
  && apt-get clean \
  && rm -rf /var/lib/apt/lists/*