* added neptune integration
* added tests for NeptuneLogger, added neptune to docs
* updated link to neptune support
* fixed docstrings, fixed try/except in tests, changed append_tags input
* fixed docstrings line lenght
* bumped epoch nr in model restore tests
* added tags support for single strings
* fixed passing neptune token to backend
* fixed project name in offline mode
* added save_top_k=-1 to checkpoint callback
* reformated initialization of neptune in online mode
* bumped epoch nr to 4 in test_load_model_from_checkpoint
* bumped epoch nr to 5
Co-authored-by: William Falcon <waf2107@columbia.edu>