pry-debugger is not available on Ruby 2.1
Require Bundler (a Gemfile) for all set up Middleman projects. We still do extension auto-discovery for "init". Gemfile may now be in any parent directory of 'config.rb', in case the Middleman project is in a subdirectory of a larger project.
Whoops, properly implement findup
Merge pull request #1194 from bhollis/gemfile

Require Bundler (a Gemfile) for all set up Middleman projects