v3

For the application:

• Fix fourcc image loading on Windows
• Fix default opened directory when selecting images on Linux and MacOSX
• GUI renamed as KantuCompareApp
• Load xkcd font if found in same directory

For development:

• Provide runnnable and reproducable steps for dependency package preparation
• Rewrite image_io.cpp related code
• Add unittest for utility functions

v0

This is the original Qt-based implementation.