Issue/29: Move mockGPT.js references to test files and out of distribution

[potench]

Issue

mockGPT.js is getting bundled in the distribution files unnecessarily.

Fix

1. Fixes mockGPT.js should not be in production bundle #29 by moving mockGPT to test files
2. Fixes warning on ReactTestUtils import

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[codecov]

Codecov Report

Merging #36 into master will increase coverage by 0.09%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #36      +/-   ##
==========================================
+ Coverage   92.94%   93.04%   +0.09%     
==========================================
  Files           7        8       +1     
  Lines         567      575       +8     
==========================================
+ Hits          527      535       +8     
  Misses         40       40

Impacted Files	Coverage Δ
src/createManager.js	92.27% <100%> (+0.1%)	⬆️
src/utils/createManagerTest.js	100% <100%> (ø)
src/Bling.js	88.44% <100%> (+0.05%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5ae8f88...df99e72. Read the comment docs.

[potench]

Ug - closing because it keeps correlating to wrong git user email.