regression test was written
images added to testdata folder
Merge pull request #66 from VladVin/Warmify_implementation

Regression test for Warmify filter, resolves #62
Merge pull request #65 from VladVin/Vignette_implementation

Regression test for Vignette, resolves #61
Add a regression test
Add images
Merge pull request #67 from KruchDmitriy/Tint_Implementation

Add a regression test for Tint filter, resolve #60
warmify.cpp was correct