* add func to set level for specific logger
* add endpoints to modify log level
* initialize base logger with IndependentLevels
* test to ensure other loggers remain unchanged
* add DELETE loggers endpoints to revert back to config
* add API docs page
* add changelog entry
* remove extraneous line
* add log level field to Core struct
* add godoc for getLogLevel
* add some loggers to c.allLoggers