audit: Add check_repository_references
audit: Add check_repository_references

Ensure that any references to HOMEBREW_REPOSITORY
are within HOMEBREW_LIBRARY.

vitorgalvao/brew,vitorgalvao/brew,vitorgalvao/brew,Homebrew/brew,MikeMcQuaid/brew,nandub/brew,nandub/brew,JCount/brew,konqui/brew,sjackman/homebrew,EricFromCanada/brew,sjackman/homebrew,konqui/brew,MikeMcQuaid/brew,JCount/brew,claui/brew,nandub/brew,claui/brew,JCount/brew,EricFromCanada/brew,MikeMcQuaid/brew,Homebrew/brew,konqui/brew,konqui/brew,JCount/brew,sjackman/homebrew,MikeMcQuaid/brew,sjackman/homebrew,Homebrew/brew,EricFromCanada/brew,claui/brew,claui/brew,vitorgalvao/brew,EricFromCanada/brew,nandub/brew,Homebrew/brew