Build statically-linked sqlcipher for Unix (#334)

dockerbuild/Dockerfile

@@ -12,9 +12,7 @@ RUN apt-get -qq update && apt-get -qq dist-upgrade && \
   # libsecret-1-dev and libgnome-keyring-dev are required even for prebuild keytar
   apt-get -qq install --no-install-recommends qtbase5-dev bsdtar build-essential autoconf libssl-dev gcc-multilib g++-multilib lzip rpm python libcurl4 git git-lfs ssh unzip \
   libsecret-1-dev libgnome-keyring-dev \
-  libopenjp2-tools \
-  # Used by Seshat
-  libsqlcipher-dev && \
+  libopenjp2-tools && \
   # git-lfs
   git lfs install && \
   apt-get purge -y --auto-remove && rm -rf /var/lib/apt/lists/*