A lot of changes and improvements!

Additions:
- MIT Licence
- Readme.md file

Changes
- Art folder created for images and fonts
- Images moved to Art folder
- Welcome screen background added
- Exo font added to folder, and the main font of the game was change to
Exo
- Filename changed from world.py to galahack.py

- Header added to galahack.py, coding, Pydoc basic info for functions
and classes.
- General source code formatting to improve readability. Reordered some
code sections and added labels to give some order.
- Changed the name of some function and variables to give better
meaning.
- Added global tick timer to begin to track movements history
- Slightly changes to Light and Dark blue colors
- Added more spaces to the current world