More extensive tests of config behavior

[lemniscate8]

I've noticed quite a few bugs and discrepancies between the initialization of a config file via a .hpp and reading from a .cfg format and just some bugs with handling data. I've added some new tests that reveal bugs and hopefully can catch future problems.

[codecov]

Codecov Report

Merging #435 (dc5cc04) into master (193c5b0) will increase coverage by 0.09%.
The diff coverage is 63.63%.

❗ Current head dc5cc04 differs from pull request most recent head 4d776e1. Consider uploading reports for the commit 4d776e1 to get more accurate results

@@            Coverage Diff             @@
##           master     #435      +/-   ##
==========================================
+ Coverage   82.75%   82.85%   +0.09%     
==========================================
  Files         297      297              
  Lines       37151    37162      +11     
==========================================
+ Hits        30746    30792      +46     
+ Misses       6405     6370      -35     

Impacted Files	Coverage Δ
tests/config/config.cpp	80.95% <63.63%> (-19.05%)	⬇️
include/emp/Evolve/World.hpp	96.68% <0.00%> (+0.31%)	⬆️
include/emp/config/config.hpp	35.89% <0.00%> (+9.15%)	⬆️

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