Add scripts for running perf and callgrind.

scripts/callgrind.bash

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+#
+set -euo pipefail
+IFS=$'\n\t'
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+
+cd "$DIR/../"
+
+RUSTFLAGS="-C opt-level=0" cargo build --no-default-features
+valgrind --tool=callgrind --callgrind-out-file=callgrind.out target/debug/compare
+
+echo "You probably want to run:"
+echo "callgrind_annotate --auto=yes callgrind.out"