Swatchbooker as a possible install option

[luzpaz]

@olivierberten mentions in https://answers.launchpad.net/swatchbooker/+question/271814 that the project will be migrating away from launchpad to github: https://github.com/olivierberten/SwatchBooker

• Update Swatchbooker on Homebrew to reflect this
  • include the changes to the proposed formula in this gist (https://gist.github.com/luzpaz/bbc019148088b5d7b93c)
• add swatchbooker to scribus homebrew install as a conditional install
• Let @oliverberten know about homebrew downstream workaround patch for the Swatchbooker formula (https://github.com/Homebrew/homebrew/blob/master/Library/Formula/swatchbooker.rb#L31-L42) and if it can get fixed in the next minor version?
  • Opened issue on Swatchbooker Github queue: Downstream fix for installing Swatchbooker via Homebrew olivierberten/SwatchBooker#1
• Start some movement to explore LCMS2 python bindings to help evolve Swatchbooker to the next level