Add a PHP solution to problem 166

Author: rdtsc

src/easy/delta-time/solutions/php/solution.php

@@ -0,0 +1,23 @@
+#!/usr/bin/env php
+<?php
+
+date_default_timezone_set('UTC');
+
+$inputFile = new SplFileObject($argv[1]);
+
+$inputFile->setFlags(SplFileObject::READ_CSV   |
+                     SplFileObject::READ_AHEAD |
+                     SplFileObject::SKIP_EMPTY |
+                     SplFileObject::DROP_NEW_LINE);
+
+$inputFile->setCsvControl(' ');
+
+foreach($inputFile as $time)
+{
+  $time = array_map(function($timestamp)
+  {
+    return new DateTime($timestamp);
+  }, $time);
+
+  echo $time[0]->diff($time[1])->format('%H:%I:%S'), PHP_EOL;
+}