Extended the EZLog Module for custom messages and append log

[kev494]

Hi

I really like your log module, but I wanted to define some custom header and footer messages. I've taken the liberty of implementing it by myself. Furthermore I implemented the ability to append an existing logfile. I also included a check, so a header or footer cannot added twice in a row. There has to be another footer or header first. Maybe you are interested to merge this changes in your module.

Kind regards, Kevin