Created global constants used by the shell to specify IO operations.
Re-organized variable declarations in global.js.
Improved word wrapping capabilities in console.js.
Refactored the HDD device driver to make it more object orienty.
Implemented the format command in the HDD device driver.
Added HDD device driver initialization code to kernel.js.
Added skeleton code for the IO operations.
Added a method 'isValid' that takes a filename as a parameter and indicates whether the filename is valid.
Modified the shell IO commands to call the appropriate kernel IO command.