Create test for validating that the tool is creating patts correctly

[pablodiegoss]

Using pymarker -p input.png, where input png is an image file that you want to create a pattern file, the output is a .patt file that contains a numbers representing each pixel of the marker in Red, Green and Blue.

Using /tests/inputs/hiro.jpg the expected output is the file /tests/inputs/hiro.patt

The test should use these two files to compare if the generate_patt function with the hiro.jpg file generates an output exactly as the hiro.patt file expected.