Dcnum

- fix: fix GPUSegmenter labeling

- feat: introduce GPUSegmenter base class
- fix: handle bytes-values in HDF5 attributes
- ref: correctly introduce `requires_background_correction` for segmenters
- setup: don't requrie cibuildwheel

- enh: some minor improvements in efficiency
- ref: increment DCNUM_PPID_GENERATION for the sake of clarity
- ref: unify dealing with num_workers and debugging

- fix: properly propagate event extraction keyword arguments
- fix: QueueCollectorThread used uint16 for enumerating indices
- fix: handle case where number of events is not multiple of chunk_size
- enh: reduce thread waiting times
- enh: add bounds check for image cache

- feat: introduce QueueCollectorThread
- feat: introduce SegmenterManagerThread
- feat: instroduce EventExtractorManagerThread and corresponding workers
- enh: minor improvements for HDF5ImageCache and ImageCorrCache
- enh: use data size as cache size if smaller than requested chunk size
- enh: return dictionary for brightness feature computation
- enh: allow to pass a single image for brightness feature computation
- enh: allow to pass a single image for texture feature computation
- enh: make sure that masks are written as uint8 to HDF5 files
- ref: haralick texture computation now returns dict instead of recarray
- ref: renamed HDF5WriterThread to DequeWriterThread
- ref: renamed feature submodules (prepended "feat_")

- enh: dataset keyword arguments and mode HDF5WriterThread
- enh: speed-up of brightness feature computation