Make iirf_h a keyword parameter (formerly fixed at 100 years)

[chrisroadmap]

Pull request

Please confirm that this pull request has done the following:

• [x] Tests added
• [x] Documentation added (where applicable)
• [x] Example added (either to an existing notebook or as a new notebook, where applicable)
• [x] Description in CHANGELOG.rst added

Fixes #4.

[codecov[bot]]

Codecov Report

Merging #58 into master will increase coverage by 0.01%. The diff coverage is 100%.

@@            Coverage Diff            @@
##           master     #58      +/-   ##
=========================================
+ Coverage   91.88%   91.9%   +0.01%     
=========================================
  Files          33      33              
  Lines        1269    1272       +3     
=========================================
+ Hits         1166    1169       +3     
  Misses        103     103

Impacted Files	Coverage Δ
fair/forward.py	83.88% <100%> (+0.17%)	:arrow_up:

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[chrisroadmap]

No rush on this one @znicholls

[znicholls]

Can you rebase onto master? It seems to be including changes from #57 too.

[chrisroadmap]

Yep, #57 was merged into master previously so the new branch includes these changes (git rebase confirms this branch is up to date with master). I've just made a small patch to the changelog and squashed it into the previous commit.

[chrisroadmap]

Awesome. Will merge when back in office next week. I don't think the 100 year time horizon was ever meant to be modified but gives users another dial they can crank. For consistency r0 and possibly also rc and rt would need to be modified as they are defined with respect to a 100 year time horizon.