Additional fixups for extract command
Additional fixups for extract command

- Rework command line options
- Make specifying a version optional
- Remove stdout option and require a tap to be specified
- Do not allow user to extract into homebrew/core
- Rework new class name generation to use existing Formulary tools

Homebrew/brew,claui/brew,maxim-belkin/brew,vitorgalvao/brew,maxim-belkin/brew,konqui/brew,nandub/brew,Homebrew/brew,konqui/brew,EricFromCanada/brew,Linuxbrew/brew,mahori/brew,reitermarkus/brew,sjackman/homebrew,EricFromCanada/brew,mahori/brew,Linuxbrew/brew,konqui/brew,Homebrew/brew,sjackman/homebrew,MikeMcQuaid/brew,JCount/brew,mahori/brew,vitorgalvao/brew,Linuxbrew/brew,sjackman/homebrew,DomT4/brew,DomT4/brew,maxim-belkin/brew,sjackman/homebrew,EricFromCanada/brew,nandub/brew,JCount/brew,reitermarkus/brew,JCount/brew,claui/brew,claui/brew,Linuxbrew/brew,DomT4/brew,JCount/brew,vitorgalvao/brew,nandub/brew,reitermarkus/brew,EricFromCanada/brew,reitermarkus/brew,mahori/brew,claui/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,konqui/brew,nandub/brew,DomT4/brew,Homebrew/brew,MikeMcQuaid/brew,vitorgalvao/brew