Issues with 21.04

* download() ThreadPool update

* update train image count

* cid + 1

* Update yolo.py

* Update export.py

* fix export grid

* Update export.py, remove detect export attribute

* rearrange if order

* remove --grid, default inplace=False

* rename exp_dynamic to onnx_dynamic, comment

* replace bs with 1 in anchor_grid[i] index 0

* Update export.py

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

* Add NMS threshold checks

* fix

* Added support for fp16 (half) to export.py

* minimize code additions

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

* Curl update

* Curl update

* Improve performance of Dataset Logger

* Fix scaling bug

* Added flag to enable/disable all inplace and assignment operations

* Removed shape print statements

* Scope Detect/Model import to avoid circular dependency

* PEP8

* create _descale_pred()

* replace lost space

* replace list with tuple

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

* add object365

* ADD CONVERSION SCRIPT

* fix transcript

* Reformat and simplify

* spelling

* Update get_objects365.py

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

* Create GlobalWheat2020.yaml

* Update and rename visdrone.yaml to VisDrone.yaml

* Update GlobalWheat2020.yaml

* Add yolov5/ to sys.path() for *.py subdir exec

* Update export.py

* Improved yolo.py profiling

Improved column order and labelling.

* Update yolo.py

* Update README.md

dependencies:
ImportError: libGL.so.1: cannot open shared object file: No such file or directory
ImportError: libgthread-2.0.so.0: cannot open shared object file: No such file or directory
ImportError: libSM.so.6: cannot open shared object file: No such file or directory
ImportError: libXrender.so.1: cannot open shared object file: No such file or directory

* replace older apt-get with apt

Code commented for now until a better understanding of the issue, and also code is not cross-platform compatible.

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

This fixes a bug where the '>' symbol in python package requirements was not running correctly with subprocess.check_output() commands.

* Add verbose and update print to logging

* Fix positonal param

* Revert auto formatting changes

* Update hubconf.py

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

* Update download() for tar.gz files

* Update general.py

* Add file_size() function

* Update export.py

* Update export.py for 2 dry runs

* Update export.py

* command line option for line thickness and hiding labels

* command line option for line thickness and hiding labels

* command line option for line thickness and hiding labels

* command line option for line thickness and hiding labels

* command line option for line thickness and hiding labels

* command line option for hiding confidence values

* Update detect.py

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

* more explicit function arguments

* fix typo in detect.py

* revert import order

* revert import order

* remove default value

* VisDrone Dataset Auto-Download

* add visdrone.yaml

* cleanup

* add VisDrone2019-DET-test-dev

* cleanup VOC

* don't resize up in load_image if augmenting

* cleanup

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

* Implement yaml.safe_load()

* yaml.safe_dump()