remove ENV/super.rb from homebrew-fork

this only has to do with building Formulae
remove metafiles.rb from homebrew-fork
remove compilers.rb from homebrew-fork
Merge pull request #8266 from rolandwalker/homebrew_remove_compilers

remove compilers.rb from homebrew-fork
Merge pull request #8265 from rolandwalker/homebrew_remove_metafiles

remove metafiles.rb from homebrew-fork
Merge pull request #8263 from rolandwalker/homebrew_remove_super

remove ENV/super.rb from homebrew-fork
read RbConfig in doctor.rb

instead of depending on Homebrew-defined constant.  This
is simpler now that we assume Ruby 2.0
require mocha/api for RSpec tests

to be removed from Homebrew-fork
strip down testing_env.rb from homebrew-fork