[Unit Testing] No more spam from testing logger.
[Unit Testing] Additional test added.
[Code Style] Style.
[Trace] Implemented recursive trace handling.
[Unit Testing] Massive refactoring done.
[Aux] Garbage collection.
[Code Style] Now it's time for scoped attributes.
[Project] Include also implementation files to ease development.
[Config] Function/method export macro variable has been added.
[Aux] Massive refactoring done over main logger class.
[API] Scoped logger wrapper now can be used with scoped attributes.
[Aux] Meaningless space replacement.
[Trace] Tiny refactoring done.
[Aux] Code style.
[Bug Fix] Fixed undefined behaviour.

There is no conditional jump depending on uninitialized value when
constructing syslog config object.
[Code Style] Wording.
[Trace] More convenient constructor for span.
[Aux] Drop deprecated comments.
[Aux] Code clean up.
[Trace] Some comments added about context_t.
[Trace] Decomposition done.