Add additional file types and functions#4

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iwatakeshi wants to merge 11 commits intokatsumeshi:masterfrom iwatakeshi:master

+18,570-56

Commits on Apr 19, 2019

Commits on Apr 22, 2019

Commits on May 7, 2019

Refactor image type detection function
iwatakeshi
committed

Commits on May 9, 2019

Update dependencies and add tests
iwatakeshi
committed