Merge branch 'hotfix/v0.0.1' into develop
remove old logger
hide the logger's implementation, only provide Logger interface
Merge branch 'feature/new_logger_interface' into develop

* feature/new_logger_interface:
  hide the logger's implementation, only provide Logger interface
  remove old logger
Merge branch 'develop'

* develop:
  hide the logger's implementation, only provide Logger interface
  remove old logger

Conflicts:
	glogger.go