• The namespace Alien::Build::Plugin::Core is reserved for plugins
  that are automatically loaded for all instances of Alien::Build
  
• Major refactor of Alien::Base2. Please do not use it.
  
• Improved documentation
  
• Added Alien::Build::Plugin::Fetch::Local
  
• Added support for ALIEN_BUILD_POSTLOAD
  
• Fixed bug where PkgConfig negotiator plugin could cause prereqs
  to get added inappropriately
  
• Make PkgConfig.pm a prereq on platforms that do not provide
  pkg-config or pkgconf.