Add bash script to run clang format on all files

tools/clang-format-all.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+read -p "Are you sure you want to run clang-format on all files in src/? (y/n) " -n 1 -r
+echo
+if [[ $REPLY =~ ^[Yy]$ ]]; then
+    find src/ -iname "*.hpp" -o -iname "*.cpp" -exec clang-format -i {} \;
+fi