Add a tool to be able to set file timestamps to git commit dates.

This will eventually be used to help improve arduino caching behavior

bin/set-timestamps-from-git

@@ -0,0 +1,16 @@
+#!/bin/bash -e
+
+# This script sets all of the files inside src and example to have mtimes
+# that match the times of the last git commit that touched each file
+
+# This can be useful when build tools depend on file timestamps to
+# make caching decisions
+
+for file in `find src examples -type f`
+do
+  timestamp=$(git log --pretty=format:%ad --date=format:%Y%m%d%H%M.%S -n 1 HEAD "$file" 2> /dev/null)
+  if [ "x$timestamp" != "x" ]; then
+    touch -t "$timestamp" "$file"
+  fi
+done
+