Qpsphere

- drop support for Python 3.5
- feat: integer grid_size allowed for square-shaped simulation
- ref: introduce RadiusExceedsImageSizeError in contour detection
- code cleanup

- BREAKING CHANGE: `models.available` is now a list, use
`models.model_dict` instead.

- BREAKING CHANGE: replace space " " by dash "-" in model names
- feat: added methods to handle third party binaries (3)
- feat: implemented `ret_qpi` for edge detection in `analyze`
- fix: example "cell_edge.py" was broken

- feat: added 2D phase fitting algorithm (method='image')
- feat: added Mie average, Rytov, and Rytov-SC models

- feat: added Mie model (based on BHFIELD) (1)
- fix: updated default keyword arguments for sphere models

- feat: added projection model
- feat: minor additions to API