* Fixing comet ml bug and adding functionality
* Updating documents
* Fixing code style issues in comet_logger
* Changing comet_logger experiment to execute lazily
* Adding tests for comet_logger and addressing comments from @Borda
* Setting step_num to optional keyword argument in log_metrics() to comply to other loggers
* Adding offline logging mode for comet_ml, updating tests and docs
* Switching to MisconfigurationException
* added comet logger
* bug fix in cases where comet was not imported before torch
* fixed mlflow logger to be consistent with docs, updated cometLogger and cometLoggers docs + flake 8 compliance