* book/ch08.xml: remove link to 'big picture' graphic. it lives in ch01 now.
* book/images/ch01dia1.png: redrawn by O'Reilly.
* book/images/ch02dia1.png: redrawn by O'Reilly.
* book/images/ch02dia2.png: redrawn by O'Reilly.
* book/images/ch02dia3.png: redrawn by O'Reilly.
* book/images/ch02dia4.png: redrawn by O'Reilly.
* book/images/ch02dia5.png: redrawn by O'Reilly.
* book/images/ch02dia6.png: redrawn by O'Reilly.
* book/images/ch02dia7.png: redrawn by O'Reilly.
* book/images/ch04dia1.png: redrawn by O'Reilly.
* book/images/ch04dia2.png: redrawn by O'Reilly.
* book/images/ch04dia3.png: redrawn by O'Reilly.
* book/images/ch04dia4.png: redrawn by O'Reilly.
* book/images/ch07dia1.png: remove.
* book/images/ch07dia2.png: redrawn by O'Reilly.
* book/images/ch07dia3.png: redrawn by O'Reilly.
