Cause install to return 1 on failure.

This fixes issue #123. Namely, the script in scripts/setup/install was
returning 0. Adding `set -e` and `set -o pipeline` causes the install
script to exit and return 1 if any part fails, including piping output
(`set -o pipeline` does this).

scripts/setup/install

@@ -1,4 +1,6 @@
 #!/bin/bash
+set -e
+set -o pipefail
 if [ "$EUID" -ne 0 ]; then
     echo "Error: The installation script must be run as root" >&2
     exit 1