Be more user-friendly to new users

* Update CONTRIBUTING.md

* Update CONTRIBUTING.md

* Update CONTRIBUTING.md

* Update CONTRIBUTING.md

* premature end of JPEG images

* PEP8 reformat
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update `check_file()`

* Update datasets.py

* supress wandb images size mismatch warning

* supress wandb images size mismatch warning

* PEP8 reformat and optimize imports
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* 'changes-in_dataset'

* Update datasets.py
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Update README.md

* added hosted images

* added new logo

* testing image hosting

* changed svgs to pngs

* removed old header

* Update README.md

* correct colab image source

* splash.jpg

* rocket and W&B fix

* added contributing template

* added social media to top section

* increased size of top social media

* cleanup and updates

* rearrange quickstarts

* API cleanup

* PyTorch Hub cleanup

* Add tutorials

* cleanup

* update CONTRIBUTING.md

* Update README.md

* update wandb link

* Update README.md

* remove tutorials header

* update environments and integrations

* Comment API image

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* double spaces after section

* Update README.md

* Update README.md
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

@KalenMike this is a PR to add image filenames and labels to our stats dictionary and to save the dictionary to JSON. Save location is next to the train labels.cache file. The single JSON contains all stats for entire dataset.

Usage example:
```python
from utils.datasets import *

dataset_stats('coco128.yaml', verbose=True)
```

* train.py GPU memory fix

* ema

* cuda

* cuda

* zeros input

* to device

* batch index 0

* Ignore Seaborn plot warnings

* Update plots.py

* Update metrics.py

* Refactoring cleanup

* Update test.py

* Refactor models/export.py arguments

* cleanup

* cleanup

* Refactor detect.py arguments

@SkalskiP @KalenMike

* unused ok

* comment arguments

* remove opt from test()

* pass kwargs

* update comments

* revert accidental default change

* multiple --img options

* add comments

Bumps [pip](https://github.com/pypa/pip) from 18.1 to 19.2.
- [Release notes](https://github.com/pypa/pip/releases)
- [Changelog](https://github.com/pypa/pip/blob/main/NEWS.rst)
- [Commits](https://github.com/pypa/pip/compare/18.1...19.2)

---
updated-dependencies:
- dependency-name: pip
  dependency-type: direct:production
...
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* Update test.py profiling

* half_precision to half

* inplace

* Multi-GPU default to single device 0

* Multi-GPU default to single device 0

* add space

Add permanent splash URL and update hyperlink from iOS landing page to Ultralytics YOLOv5 landing page at https://ultralytics.com/yolov5