Merge pull request #15 from euroelessar/master

[API] Added logger_verbosity_traits.
Merge pull request #16 from euroelessar/master

[API] Use LWP on Linux instead of TID.
[Bug Fix] Forgotten include added.
[Code Style] Comment and code style.
[Aux] Code reordering.
[TCP] Write handler will now block until the message is completely sent.
[Code Style] Reordering.
[Thread Safety] Socket sink's thread-safety is now properly handled.
[Aux] Refactoring over socket sink.

 - Exporting public typedefs.
 - Renaming.
[Code Style] Style.
[Code Clean] Refactoring done over tcp backend.

 - Export public typedefs.
 - Removed deprecated member fields prefix.
 - Code style.
[Code Clean] The similar refactoring over udp backend.
[Thread Safety] All sinks are now thread-aware.
[Code Style] Just merger PR has been slightly refactored.
[Aux] Added `locked_ptr` synchronize primitive.
[API] Method renaming done.
[API] Logger can now provide its tracking state outside.
[Aux] Bool logger variables are now atomic.
[Unit Testing] Partially tested logger swapping.
[Unit Testing] Another part of partial swapping has been tested.
[Aux] Initialization sequence has been changed.
[Tasks] One more task.
[Version] Bump.