Deepflash2

-- Bug fixes
-- Adding Code-based Tutorial (https://matjesg.github.io/deepflash2/tutorial_monuseg.html)

New Features

- new features ([42](https://github.com/matjesg/deepflash2/pull/42)), thanks to [matjesg](https://github.com/matjesg)
- Multiclass GT Estimation, closes 34
- Torchscript ensemble class for inference / tta adjusted
- ONNX export possible


- Major changes
- Different classes for training (EnsembleLearner) and Inference (EnsemblePredictor)
- Normalization based on uin8 images (0...255)

- Instance segmentation metrics ([32](https://github.com/matjesg/deepflash2/pull/32)), thanks to [matjesg](https://github.com/matjesg)
- Instance segmentation metrics for GT estimation and prediction

- Dependency fix (opencv-python-headless>=4.1.1,<4.5.5)
- Minor improvements and fixes

- Fixes bug when predicting on new data.

- Removing git dependency for cellpose installation.

- Bug fixes and minor improvements.