Create sudoku namespace and Board class

Add two js files and link in index.html.  Sudoku.js contains a namespace
and the main 'run' loop.  Board class has a prototype with various
methods (including init) to be called by board instancs.
Create object to store/supply sudoku board states

Add SUD.sudoStates object with method that returns a sudoku board state
as an 81-length array of numbers.  More 'default' layouts can be added
here as methods, and later on perhaps a method to load from JSON or
other formats.