Support Parse.File getData cancel

[dplewis]

Allow to cancel downloading file data or uploading via uri (uri is first downloaded to base64 then uploaded to the server).

[codecov]

Codecov Report

Merging #951 into master will decrease coverage by 0.02%.
The diff coverage is 89.47%.

@@            Coverage Diff             @@
##           master     #951      +/-   ##
==========================================
- Coverage   91.94%   91.92%   -0.03%     
==========================================
  Files          54       54              
  Lines        5064     5076      +12     
  Branches     1137     1139       +2     
==========================================
+ Hits         4656     4666      +10     
- Misses        408      410       +2

Impacted Files	Coverage Δ
src/ParseFile.js	96.17% <89.47%> (-0.91%)	⬇️

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[acinader]

this looks good to me. I have a question about how you're handling and keeping track of abort.

[dplewis]

@acinader I have made the requested changes

[acinader]

nice. this is cool.

[dplewis]

Thanks for reviewing!