Adding require.js and Underscore.js to the repository.
Moved require.js
Sudoku Code Reorg

Moved *BasicMockSudokuGame.js* from the **test** folder to the
**sudoku** folder.

Removed the namespace objects **Sudoku** and **SudokuTest** from the
Sudoku source files.
Added require.js module for the sudoku code, Sudoku.js
Added main.js

require.js will use main.js as the place where code execution starts.
Update index.html to handle the new changes

index.html is not yet using require.js.  It's still using `<script>`
tags to load scripts.
Ignoring .DS_Store file
Fixed use of require in main.js

Used paths to simplify the **require** call.  Fixing this fixed
**index-require.html**.
Fixed useage of require in Sudoku.js

Used **paths** in the `require.config()` call to simplify the define
statement.
Added index-require.html

I added index-require.html to test the use of require in the project.
I will eventually replace index.html with the contents of this file.