[PATCH] Adding user documentation for UseAuto transform

[Edwin Vane]

  Changes made. Thanks for the feedback. Clearly I've been reading the spec too much and forgot my audience in places.

  As for your random idea silvas, that sounds like an interesting clean-up pass. If a type is never used though it won't appear in the AST right? How would we find such dead code?

http://llvm-reviews.chandlerc.com/D508

BRANCH
  docs

ARCANIST PROJECT
  clang-tools-extra