Log::Dispatch::Config TODOs

Here's my TODOs for Log::Dispatch::Config.

1. format code needs clean up

   %d{%Y-%m-%d} looks quite messy, if we wanna change this, we should do it ASAP, before this module becomes stable/standard.

2. caller stack

   Current code to get stack level depends heavily on Log::Dispatch internal implementation.

3. Exception handling in Logging

   Currently when something bad happened in Log::Dispatch::*, just exception is thrown. It might be trouble for mission critical task with debug logging on.

4. LogLevel config depending on caller package like Log4j

   Maybe we don't need it!