Fixed deploy from file on IE

[floreks]

Fixes #430

According to documentation:
https://developer.mozilla.org/en-US/docs/Web/API/FileReader/readAsBinaryString

reader.readAsBinaryString is deprecated and should not be used. As we are reading text file I've changed it to readAsText. By default it assumes UTF-8 encoding.

[bryk]

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Reviewed 1 of 1 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from the review on Reviewable.io

[codecov-io]

Current coverage is 82.29%

Merging #478 into master will not affect coverage as of dd9074e

@@            master    #478   diff @@
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  Files           79      79       
  Stmts          644     644       
  Branches         0       0       
  Methods          0       0       
======================================
  Hit            530     530       
  Partial          0       0       
  Missed         114     114       

Review entire Coverage Diff as of dd9074e

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