[antlr-interest] correction about book pricing

[Terence Parr]

Hi...from the editor:

> OK actually I was somewhat incorrect about the price of beta book  
> and paper
> book combo.
>
> As an example, here is the price structure for Rails for Java  
> Developers
> (another book I'm editing right now that is in beta):
>
> Retail price for paper book alone: 34.95
> Price on Amazon (Amazon always discounts below retail price): 23.07
> Combo pack price on Pragmatic Bookshelf site (beta book PDF and  
> paper book):
> 43.75
> PDF alone on Pragmatic Bookshelf site: 22.00
>
> So . . . combo of beta PDF and paper book is about $9 more than retail
> price. That includes final PDF of book when it is available, too.  
> Still a
> good deal.

Terence