Utils/Logger: FileTarget implementation

Utils/Logger: Implement message routing -> logging library is working now
Move 'nil' class into Utils/mpl.hh

Utils/Logger: Documentation
Utils/Logger: Better SENF_LOG_CLASS_AREA integration
Utils/Logger: Fix compile-time config bug for larger configurations

Logger: Implemented compile-time configuration support

PPI: Add documentation
Utils: Make Logger macros define empty stub types

Typo fixes

Unified emacs Local Variables