Add setup script for example dev environment

Eliminates the need for the scripts change their own sys.path. Also gets
the non-stock dateutil.parser

example/aitf/ancil.py

@@ -20,7 +20,6 @@
 import os
 import sys
 import datetime as dt
-#sys.path.append(os.path.abspath(os.path.dirname(__file__)+'/../..'))
 import csppfetch
 import csppfetch.daterange
 from csppfetch.roundtozero import roundtozero

example/setup-testing

+#! /bin/sh
+set -e
+
+run() {
+	# I'm not using "set -x" because activate/deactivate are unhelpfully noisy
+	echo "$@"
+	"$@"
+}
+
+run python3 -mvenv venv
+run . venv/bin/activate
+run pip install python-dateutil -q
+run deactivate
+run ln -s venv/lib/python3.6/site-packages/six.py .
+run ln -s venv/lib/python3.6/site-packages/dateutil .
+run ln -s ../csppfetch .
+# Test modules are available
+run python3 -c "import dateutil.parser"
+run python3 -c "import csppfetch"