Updates to README, Travis, test coverage

[opiethehokie]

No description provided.

[codecov]

Codecov Report

Merging #27 into master will increase coverage by 0.89%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #27      +/-   ##
==========================================
+ Coverage   90.12%   91.02%   +0.89%     
==========================================
  Files           2        2              
  Lines         243      245       +2     
==========================================
+ Hits          219      223       +4     
+ Misses         24       22       -2

Impacted Files	Coverage Δ
conda_mirror/conda_mirror.py	90.9% <100%> (+0.9%)	✅

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[ericdill]

Thanks @opiethehokie . I think that definitely clarifies usage in the readme and improving the test coverage is always welcome 🎉