BASIC Games to Javascript Files

For the "101 Basic Computer Games" porting project, this ConsoleWindow will be used
as the output device in each ported game. The ConsoleWindow is posted in two formats:

ConsoleWindow.js - Javascript source file with just the ConsoleWindow code for inclusion
                   into an HTML page

console_v1.html  - All-in-one demo file illustrating use of the ConsoleWindow.


console_v1.html
---------------
This is an all-in-one file containing V1 of the Javascript ConsoleWindow with some supporting
test capability. This demonstration file creates an 80x24 ConsoleWindow, and exposes methods
to write text with or without a trailing line feed, clearing the screen, and accepting user
input.

Constructor: ConsoleWindow(columns, rows, size)
- columns: Integer - Number of columns for console
- rows: Integer - Number of rows for console
- size: Optional - one of five enumerations
        Tiny, Small, Normal, Big, Large. 
        If omitted, "Normal" is used (14px font)

The methods of each ConsoleWindow instance:

write(text)

Display a line of text at the current cursor position without returning the cursor
to the left side of the display (no "carriage return/linefeed"). 

writeLine(text)

Display a line of text at the current cursor position, returning the cursor
to the left side of the display (includes trailing "carriage return/linefeed"). 

clear()

Clears the console display and moves the cursor to the upper left-hand corner.

readLine(callback)

Displays a "_" prompt at the current cursor location and expects user input, terminated
by the [ENTER] key. Sends the entered text string back to caller via the provided callback
function, eg callback expected to be of form expecting one parameter.