BYOL: Move unnecessary dependencies to "if __name__ == '__main__'" section

[sorenrasmussenai]

Move imports, to the "if name == 'main' section.

What does this PR do?

Avoids importing unnecessary stuff, among them a cv2 import via the SimCLR transform modules, when importing BYOL

[pep8speaks]

Hello @sorenrasmussenai! Thanks for updating this PR.

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2020-09-01 20:41:05 UTC

[codecov]

Codecov Report

Merging #176 into master will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #176      +/-   ##
==========================================
- Coverage   91.03%   91.03%   -0.01%     
==========================================
  Files          89       89              
  Lines        4073     4071       -2     
==========================================
- Hits         3708     3706       -2     
  Misses        365      365              

Flag	Coverage Δ
#unittests	91.03% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...l_bolts/models/self_supervised/byol/byol_module.py	96.29% <100.00%> (-0.14%)	⬇️

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