adds meaningful exception for mismatched image sizes

[djkapner]

nway cell matching expects that the average projection images in the container are all the same size. The current failure mode relies on opencv.phaseCorrelate failing with the error message:

cv2.error: OpenCV(4.4.0) /tmp/pip-req-build-99ib2vsi/opencv/modules/imgproc/src/phasecorr.cpp:524: error: (-215:Assertion failed) src1.size == src2.size in function 'phaseCorrelate'

This PR adds an early check, a test for the check, and a more informative message:

__main__.NwayException: not all experiments have the same size average projection images, which nway matching currently expects. sizes and image paths are
(449, 512): /allen/programs/braintv/production/visualbehavior/prod0/specimen_789992909/ophys_session_815485890/ophys_experiment_815652334/processed/ophys_cell_segmentation_run_1080895240/avgInt_a1X.png
(449, 512): /allen/programs/braintv/production/visualbehavior/prod0/specimen_789992909/ophys_session_817101568/ophys_experiment_817267785/processed/ophys_cell_segmentation_run_1080850339/avgInt_a1X.png
(447, 512): /allen/programs/braintv/production/visualbehavior/prod0/specimen_789992909/ophys_session_819949602/ophys_experiment_820307518/processed/ophys_cell_segmentation_run_1080863409/avgInt_a1X.png
(447, 512): /allen/programs/braintv/production/visualbehavior/prod0/specimen_789992909/ophys_session_820871900/ophys_experiment_821011078/processed/ophys_cell_segmentation_run_1080861432/avgInt_a1X.png
(447, 512): /allen/programs/braintv/production/visualbehavior/prod0/specimen_789992909/ophys_session_822388759/ophys_experiment_822647135/processed/ophys_cell_segmentation_run_1080895280/avgInt_a1X.png
(447, 512): /allen/programs/braintv/production/visualbehavior/prod0/specimen_789992909/ophys_session_824745199/ophys_experiment_825130141/processed/ophys_cell_segmentation_run_1080861930/avgInt_a1X.png

[codecov-io]

Codecov Report

Merging #63 (5383ffd) into main (30ce5fe) will increase coverage by 0.02%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #63      +/-   ##
==========================================
+ Coverage   97.59%   97.62%   +0.02%     
==========================================
  Files           9        9              
  Lines        1041     1052      +11     
==========================================
+ Hits         1016     1027      +11     
  Misses         25       25              

Impacted Files	Coverage Δ
nway/nway_matching.py	97.07% <100.00%> (+0.16%)	:arrow_up: