Ptufile

- Add PtuFile.scanner property.
- Add numcodecs compatible PTU codec.

- Support sinusoidal scanning correction.

- Change positive dtime parameter from index to size (breaking).
- Fix segfault with ImgHdr_TimePerPixel = 0.
- Rename MultiHarp to Generic conforming with changes in PicoQuant reference.

- Fix empty line when first record is start marker.

- Change image histogram dimension order to TYXCH (breaking).
- Change frame start to start of first line in frame (breaking).
- Improve trimming of incomplete frames (breaking).
- Remove trim_dtime option (breaking).
- Fix selection handling in PtuFile.decode_image.
- Add option to trim T, C, and H axes of image histograms.
- Add option to decode histograms to memory-mapped or user-provided arrays.
- Add ``__getitem__`` interface to image histogram.

- Initial alpha release.