include documentation for fusion mode

[cying111]

• update readme to include a section on fusion mode
• re-format the release history

[codecov-commenter]

Codecov Report

Merging #373 (1434aa3) into devel (b2f57d3) will not change coverage.
The diff coverage is n/a.

❗ Current head 1434aa3 differs from pull request most recent head 02d2d50. Consider uploading reports for the commit 02d2d50 to get more accurate results

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@@           Coverage Diff           @@
##            devel     #373   +/-   ##
=======================================
  Coverage   86.43%   86.43%           
=======================================
  Files          24       24           
  Lines        3221     3221           
=======================================
  Hits         2784     2784           
  Misses        437      437           

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