Handle more file with more than 2GB size, reimplement transform

[franke1276]

file size was stored in a Int. so we can not handle files with more than 2GB

changed to a Long value

[codecov-io]

Current coverage is 76.83% (diff: 11.11%)

Merging #83 into master will decrease coverage by 0.51%

@@             master        #83   diff @@
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  Files            32         32          
  Lines          1042       1049     +7   
  Methods         976        985     +9   
  Messages          0          0          
  Branches         66         64     -2   
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  Hits            806        806          
- Misses          236        243     +7   
  Partials          0          0          

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[harsha2010]

can you add a test for the transform method of Polygon and I will pull the PR in once it passes