Added easylogging++ library and integrated it into manager.cpp.
Started work on own logging facility.
Using a shared_ptr for the stringstream in the LoggingStream class.
Added log levels.
Renamed LoggingStream to LogStream to keep consistency.
Improved handling of different loggers with different names.
Added gpl headers to logging.h/cpp.
Added file/line to Logger (only for verbose logging in the future).
Started work on log sinks.
Added LogOutputSink and other (still empty) sinks like syslog, file log
Fixed a small bug with the formatted sinks outputting the same things
again and again.
Removed unnecessary util::str.
LogSink's have the right to have names too!
Replaced all std::cout/cerr in manager.cpp with log commands.
Implemented verbosity handling.
Added a date to the formatted logging sinks.
Replaced some old c time functions with more c++ functions.
Added a maximum_verbosity attribute to the log manager.
Removed complete path from %(file).
Merge branch 'master' into mapcrafter_library