Update section on integerLibrary, expand build ways example
Update section on integerLibrary, expand build ways example

See #179
sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,snowleopard/hadrian,sdiehl/ghc,izgzhen/hadrian,bgamari/shaking-up-ghc,sdiehl/ghc,snowleopard/shaking-up-ghc,sdiehl/ghc