Add wrapper around MD_STD::strtotime() that will throw an expected

exception

src/MD_STD.php

@@ -303,6 +303,27 @@ final class MD_STD {
 
     }
 
+    /**
+     * Wrapper around self::strtotime() that will return MDParseException (an expected
+     * exception) rather than MDInvalidInputDate (an unexpected exception).
+     *
+     * @param string $datetime String to convert.
+     *
+     * @return integer
+     */
+    public static function strtotime_for_public_apis(string $datetime):int {
+
+        try {
+            $output = self::strtotime($datetime);
+        }
+        catch (MDInvalidInputDate $e) {
+            throw new MDParseException($e->getMessage());
+        }
+
+        return $output;
+
+    }
+
     /**
      * Initializes a curl request with the given presets.
      *