Visual quality control tool

Ссылка на задачу в bitbucket: https://bitbucket.org/barsique/visual-quality-control-tool/issues/4/stage-1-basic-creating-a-class-responsible

Описание задачи:

Creating a class responsible for comparing the resulting screenshot from the Chrome / Chromium browser with the evaluation file. The class should be do the following:

1. Checking availability png-file generating from browser and evaluation png-file.
2. Using the class method responsible for comparing two graphic files - screenshot from browser and the evaluation file. If the contents of the graphic files are different from each other then need to create a comparative graphic file with the specified areas in which the changes occurred (in addition, you can deduce in percentage of how different the files compare from each other).
3. If for some reason there are errors in the program when using this class, needed generate the appropriate exceptions with a brief description of the error.