run-tests.sh: Add support for coverage report

This requires the coverage python module. You enable it by calling
run-tests.sh with the --coverage (-c) flag.

run-tests.sh

@@ -1,2 +1,25 @@
 #!/bin/sh
-PYTHONPATH=lib nosetests --all-modules
+
+OPTS='--all-modules '
+
+die() {
+	echo Error: "$@"
+	exit 1
+}
+
+while [ "$#" -gt 0 ]; do
+	case $1 in
+		-c|--coverage)
+			OPTS="$OPTS --with-coverage"
+			;;
+		-*)
+			die "Unknown option: '$1'"
+			;;
+		*)
+			die "Unknown argument: '$1'"
+			;;
+	esac
+	shift
+done
+
+PYTHONPATH=lib nosetests $OPTS