Fix #298, resetting config option

[henryiii]

Add a test, and make sure this gets reset.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@68c8b1b). Click here to learn what that means.
The diff coverage is 100%.

@@           Coverage Diff           @@
##             master   #301   +/-   ##
=======================================
  Coverage          ?   100%           
=======================================
  Files             ?     12           
  Lines             ?   2884           
  Branches          ?      0           
=======================================
  Hits              ?   2884           
  Misses            ?      0           
  Partials          ?      0

Impacted Files	Coverage Δ
include/CLI/App.hpp	100% <100%> (ø)

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