Configuration loader for easy_logging with yojson backend

Provides deserialisation of logging configuration (loggers instantation and handlers parameters) from json, using ppx_deriving_yojson.

 Logging infrastructure inspired by the Python logging module.

The aim of this module is to provide a quick and easy to use logging infrastructure.

It has the following features :

• one line logger creation
• log messages printf style, or [string] or [string lazy_t]
• tree logging architecture for light configuration
• handlers associated to each logger will format, filter and treat the message independantly.
• use the infrastructure with your own handlers with the [MakeLogging] functor.
• use tags to add contextual information to log messages