If you stopped at the computer icon (icons are little pictures) that identifies the State-of-the-Art Contractor feature expecting another one of Morris Carey's fine columns, please beware. This column was not created on — or for — an IBM PC. The machine I use, and will write about every other month, is what its maker Apple Computer Co. once described as the "computer for the rest of us" — the Macintosh. To say that I use a Macintosh is an understatement. I run my business entirely on the Mac, using it for letters, estimates, accounting, and payroll. I have also used my Macintosh to create market plans, publish a newsletter, and forecast business trends. It can fill out forms, address mailings,