four-color checkerboard

[jeff-regier]

This PR replaces the two-color checkerboard with a four-color checkerboard. It also includes changes to the encoder architecture. The new variational family more accurately approximates the posterior distribution; it doesn't change the accuracy of point estimates much though.

[codecov]

Codecov Report

Attention: Patch coverage is 88.46154% with 18 lines in your changes missing coverage. Please review.

Project coverage is 92.52%. Comparing base (0068357) to head (3220fd1).

Files	Patch %	Lines
bliss/encoder/encoder.py	81.94%	13 Missing ⚠️
bliss/encoder/image_normalizer.py	37.50%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1025      +/-   ##
==========================================
+ Coverage   91.54%   92.52%   +0.98%     
==========================================
  Files          24       25       +1     
  Lines        3158     3132      -26     
==========================================
+ Hits         2891     2898       +7     
+ Misses        267      234      -33     

Flag	Coverage Δ
unittests	92.52% <88.46%> (+0.98%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.