Update ZNC to v1.6.1

And also restructure the Dockerfile a bit.

docker-entrypoint.sh

@@ -0,0 +1,35 @@
+#! /usr/bin/env bash
+
+# Options.
+DATADIR="/znc-data"
+
+# Build modules from source.
+if [ -d "${DATADIR}/modules" ]; then
+  # Store current directory.
+  cwd="$(pwd)"
+
+  # Find module sources.
+  modules=$(find "${DATADIR}/modules" -name "*.cpp")
+
+  # Build modules.
+  for module in $modules; do
+    cd "$(dirname "$module")"
+    znc-buildmod "$module"
+  done
+
+  # Go back to original directory.
+  cd "$cwd"
+fi
+
+# Create default config if it doesn't exist
+if [ ! -f "${DATADIR}/configs/znc.conf" ]; then
+  mkdir -p "${DATADIR}/configs"
+  cp /znc.conf.default "${DATADIR}/configs/znc.conf"
+fi
+
+# Make sure $DATADIR is owned by znc user. This effects ownership of the
+# mounted directory on the host machine too.
+chown -R znc:znc "$DATADIR"
+
+# Start ZNC.
+exec sudo -u znc znc --foreground --datadir="$DATADIR" $@