constantinpape/torch-em: Support for 4d data and several other fixes

• Small fix by @oeway in https://github.com/constantinpape/torch-em/pull/31
• Hpa dataset by @constantinpape in https://github.com/constantinpape/torch-em/pull/32
• fix input for ilastik predictor by @JonasHell in https://github.com/constantinpape/torch-em/pull/33
• add boolean to set ilastik threads to 0 by @JonasHell in https://github.com/constantinpape/torch-em/pull/34
• add plt functionality for check_loader by @JonasHell in https://github.com/constantinpape/torch-em/pull/35
• fix n_sample bug in rawDataset and plt bug in check_loader by @JonasHell in https://github.com/constantinpape/torch-em/pull/36
• fix bugs for pseudo-label learning by @JonasHell in https://github.com/constantinpape/torch-em/pull/37
• Update for new build_model signature by @constantinpape in https://github.com/constantinpape/torch-em/pull/38
• Implement shallow2deep for multi-class predictions by @constantinpape in https://github.com/constantinpape/torch-em/pull/39
• Enable partial deserialization of raw and segmentation dataset by @constantinpape in https://github.com/constantinpape/torch-em/pull/40
• Enable prediction with channels and add test for it by @constantinpape in https://github.com/constantinpape/torch-em/pull/41
• Support 4d data and labels with channels in segmentation dataset by @constantinpape in https://github.com/constantinpape/torch-em/pull/42

• @oeway made their first contribution in https://github.com/constantinpape/torch-em/pull/31
• @JonasHell made their first contribution in https://github.com/constantinpape/torch-em/pull/33

Full Changelog: https://github.com/constantinpape/torch-em/compare/0.2.0...0.3.0