OpenPIV - Python an open source particle image velocimetry (ver. 0.22.0)

This release combines several improvements:

1. first 3D version (new contribution, see the authorship by commits)
2. automatic Github actions build of binary wheels for installation without compilers
3. removed appveyor build as obsolete

fixed windows conda-forge failure with encoding

0.21.8b

Update setup.py

trying lower numpy requirements for conda-forge

0.21.8a

Delete conda_build_config.yaml

fixed setup issues

can be now installed from

pip install cython numpy
pip install git+https://github.com/openpiv/openpiv-python --force-reinstall

added conda_build_config - it might solve the Conda-forge problem

Update README.md

from conda-forge that I cannot make working to anaconda that I get with
conda build .
anaconda upload --user openpiv <path-to-build>

fixed y-direction bug, added piv.piv() example with animation

improved setup

added synthetic image generator

@tomerast prepared synthetic image generator with examples - in the future we need to develop tests based on synthetic images

fixed a small bug in the setup (.pyx wasn't included)

Merge pull request #113 from alexlib/synimage

Synthetic image generator by @tomerast

PIV mutlipass with window deformation

Thanks to @TKaeufer we have now also the window deformation algorithm in OpenPIV. Please see the example under examples/tutorials and the notebook linked in the Readme.md

Updated structure for easier import and installation using binary wheels

0.21.2b

bumped to 0.21.2b for release