0.7.7
 - enh: add QPImage meta data keys "date", ""numerical aperture",
   "pos x", "pos y", and "time"
 - ref: minor cleanup
0.7.6
 - ref: deprecate "hologram" input type in favor of "raw-oah"
0.7.5
 - enh: write HDF5 image metadata so that HDFView 3.1.1 can
   visualize the phase data
 - docs: several minor fixes
0.7.4
 - enh: add QPImage meta data keys "angle", "focus", "device",
   and "software"
0.7.3
 - fix: strip third axis from input hologram images
0.7.2
 - fix: subclass MetaDict from collections.UserDict instead of dict
   (TypeError super() argument 1 must be type, not dict)
 - docs: fix rtd build
0.7.1
 - fix: easy fix for regression in h5py with backing_store=False
0.7.0
 - feat: allow to set hologram filter size in Fourier indices
   (Fourier space pixels) instead of relative to the distance
   between central band and side band by setting the argument
   "filter_size_interpretation" to "frequency index"
 - fix: Fourier filter size for holograms is now inclusive,
   i.e. points *on* the perimeter of the filter are included
 - setup: bumpy nrefocus from 0.2.1 to 0.4.3 (use new interface)
 - ref: remove IMAGE_* attributes from HDF5 datasets, because they
   anyway only work with uin8 data, and not with float data
 - ref: code cleanup
0.6.4
 - setup: bump nrefocus from 0.2.0 to 0.2.1
0.6.3
 - docs: fix sphinx build
 - tests: fix tests due to newer h5py version
 - ref: fix numpy 1.20.0 deprecation warnings
 - ci: migrate to GitHub Actions
 - setup: setup.py test is deprecated
0.6.2
 - maintenance release
0.6.1
 - maintenance release
0.6.0
 - feat: automatically remove 2PI phase offsets when instantiating
   a QPImage (The phase offset is estimated from a 1px-wide border
   around the image)
 - feat: allow to disable the processing of phase data (unwrapping
   and correcting for phase offset) using ``proc_phase=False``
   when instantiating a QPImage
0.5.4
 - docs: minor improvements
0.5.3
 - tests: minor improvements
0.5.2
 - enh: do not compress image data when HDF5 "core" driver is used
 - ref: fix deprecated `.value` (h5py)
0.5.1
 - ref: allow to subclass meta.MetaDict
 - docs: fixed several minor typos 
0.5.0
 - feat: slicing of QPImage objects preserves background data, but
   background is merged from existing background data
0.4.6
 - docs: fix typos
0.4.5
 - docs: add HDF5 file format description
0.4.4
 - maintenance release
0.4.3
 - fix: use memory address in QPImage.__repr__ if identifier not given
 - fix: only use meta.DATA_KEYS in QPImage.__eq__
 - cleanup: remove unused "dm exclude" meta.DATA_KEYS definition
0.4.2
 - fix: minor identifier ambiguity
0.4.1
 - docs: add example of mask-based correction with qpsphere
 - docs: minor cleanup
0.4.0
 - BREAKING CHANGE: replace all occurences of "binary"
   with "mask" to avoid ambiguities
0.3.0
 - feat: new meta data key "sim model"
0.2.1
 - ci: automate PyPI release with travis-ci
0.2.0
 - drop support for Python 3.5
 - docs: add QPSeries example to user API section
 - feat: `QPSeries.get_qpimage` supports QPImage identifier as index
 - feat: allow to set data storage dtype, which now defaults to float32
   to save disk space.
 - fix: set default gzip compression level to 9
 - ref: unify image data storage, set hdf5 chunks to image size
0.1.8
 - code cleanup
0.1.7
 - fix: bad default keyword argument in bg_estimate.estimate
0.1.6
 - implement qpimage refocusing function `QPImage.refocus`
 - API change: renamed "ramp" correction to "tilt" correction
 - add identifier to represenation string in QPImage
 - hologram analysis:
   - add disk, square, and tukey filters
   - standard "gauss" filter is replaced by "disk" filter 
   - standard filter size is set to one third of the distance
     between the sideband and the central band
   - allow to set hologram-retrieval parameters as a keyword
     argument "holo_kw" in QPImage
0.1.5
 - support nan values in phase data
 - add fletcher32 checksums and gzip compression to hdf5 files (#10)
 - allow to hard-link background-correction data in QPSeries
0.1.4
 - more __init__ checks for QPImage and QPSeries (user convenience)
 - allow negative indices in QPSeries.get_qpimage
 - Bugfix: `bg_estimate` does not compute intersection but union (#9)
0.1.3
 - add QPImage.raw_amp and QPImage.raw_pha
 - improve QPImage.__eq__
 - add "identifier":
   - meta data key
   - keyword for QPSeries.add_qpimage
   - property of and keyword for QPSeries
 - add convenience functions for item access in QPImage and QPSeries
 - moved to pathlib
 - minor API changes
0.1.2
 - allow strings and lists for `which_data` everywhere (#1)
 - check for valid background keys in image_data.py (#2)
 - add QPImage.info property (#5)
 - add slicing (#6)
 - add references to documentation (#7)
0.1.1
 - QPImage.set_bg_data now accepts QPImage objects
 - add QPSeries for managing multiple QPImages in one hdf5 file (#3) 
0.1.0
 - initial release
