[Book] Update chapter 3 to include prerequisite information that was in chapter 5. Update bit about registers and how they are allocated. Remove deprecated stuff about temporary registers and register spilling. More to do.
[Book] Update chapter 3 to include prerequisite information that was in chapter 5. Update bit about registers and how they are allocated. Remove deprecated stuff about temporary registers and register spilling. More to do.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@32644 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

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