Rapidtide

* (docs) Removed duplicate funding source. Hopefully this will resolve the Pypi upload issue.

* (docs) Added some new sections to theory.
* (package) Completely changed the way I handle and distribute test data. This makes the package much smaller (~17M), which should fix pypi deployment. This involved several changes to the Docker and circleCI workflows, which I think are now stable.

* (examples) Separated essential test data from developer test data to make the installation much smaller.
* (package) Major modernization to package build and test files.

* (rapidtide) Some work on phase permutation for null correlation calculation.
* (happy) Put in the skeletons of some new features (upsampling, optical flow calculation).
* (OrthoImageItem.py) Removed the last of the obsolete pyqtgraph calls.
* (package) Attempting to modernize the packaging scripts to avoid deprecated behavior.
* (package) Several changes to fix the build environment.

* (rapidtide) Added ability set a threshold value for "equivalence" of spatial dimensions of NIFTI files (rather than requiring an exact match) using the ``--spatialtolerance`` option.
* (rapidtide) Added "offset masks" to set the region that defines "zero" time offset.
* (fingerprint) Added several new summary statistics for each region.
* (fingerprint) Allow the use of 3D masks with 4D data.
* (tidepool) Resolve a deprecation in Qt.
* (tidepool) Made tidepool less chatty by default (default verbosity is now 0).
* (Docker) Cleaned up the container build.
* (package) Critical bug fix for multiprocessing in python versions 3.10 and above ("10" < "8"! Who knew?)
* (package) Added ".csv" files as a supported text file type.
* (package) Improved version handling when in a container.
* (reference) Added XML files to make the JHU arterial atlases loadable in FSLeyes.

* (package) Spruced up all the progress bars with tqdm.
* (deployment) Improved the testing structure to cache environment builds.
* (Docker) Build python environment with pip rather than conda now.