Unspecified positional mapping has been implemented.

Another json formatter renaming done.
And renaming again. Some comments added.
Json formatter decomposition done.
Code style.
Formatter config initialization has been reviewed.

Now all base configs should be boost::any, which is constructed after config file parsing.
That config is passed through `factory_traits`, creating native config, which represents true formatter configuration.

This changes helps to create complex config trees.
Fix build on GCC 4.4.