Code style.
Reduce code duplicates.
Forgotten include added.
Tiny renaming done.
Refactoring over factory traits methods.
Styling.
More proper place for keyword helper functors.
Renaming again.
Huge package decomposition done.

Factory traits has been splitted. More comments added. Useless test removed.
Set watcher has been moved into separate file.
Drop unused header.
String/stream frontend is now default instead of string/files.

Tests and examples has been synchronized.
Actually it doesn’t modify object’s state.
One task less.
Synchronizing example.
Some renaming done.
Now repository throws exception if sink/formatter with specific unique name is not registered.
More verbose error message now returned with exception if failed to convert `boost::any` type to necessary.
Comments styling fix.
Code style.