Wonho

-   A test file - 'tests/TestSkills.java' is added. Test module is
    updated to run this test file.

-   A new module - 'skills' is added. It has categorized skill sets -
    phisical attacks, offensive buffers, and defensive buffers (will
    be added soon) with their few skills (methods) and interfaces - 
    names, effects.

-   A file 'tests/README' is updated. A log file
    'update/updates_by_wono.log' is updated.