Finished refactoring logic.js.
- closed #14
- application now augments its modules with a customized log method
- random ships can be added to the level with different or random orientations
- level and config files moved to different folders
- environments can now be defined separately and reused among different levels
- utility function moved from classes.js to utils.js
- added matrix functions to:
  * create a matrix from another or an array
  * print 3x3 matrices
  * get a row of a matrix
- matrix inverse functions improved by avoiding equality checking