This adds the code to generate the homebrew-core.json file which
represents the entire tap instead of just the previous array of
formula hashes. Any shared logic has been moved into the top-level
hash scope including aliases, renames, tap_git_head and tap_migrations.
I also added a check to skip adding the variations hash to the api
hash if it is empty.
Now we're down to 10MB from 24MB!!!
ba3a0f8c33