Add I2C logger script.

packages/usb/log-i2c-errors.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+(
+startTime=`date +%s`
+while true; do
+    s="$((`date +%s`-$startTime))"
+    echo "$((s/60/60)):$((s/60)):$((s))"
+    for i in `seq 0 5`; do ./get-slave-i2c-errors.js $i; done
+done
+) 2>&1 | tee $1