Lots of changes:

* Splitting the log watcher from the log mailer
* There’s lots of stuff specific to a Nginx/PHP-FPM/FastCGI stack that is used in the processing in the mailer, which needs to be abstracted for it to be useful in other scenarios
* It globs messages in to threads, but we need to add a thread ID for some clients (we rely on subject atm)
* Each thread of output from nginx is given a unique sha so that individual output can be followed across widely globbed threads
* Takes arguments, but there’s no sanitisation or help (we should look in to leveraging a library for this, found a few but none seemed standard)