* global: add RUBY_TWO global variable.
* test-bot: use RUBY_TWO global variable.
* github: produce better curl error messages.
If we don't know why curl has failed then ensure that the error messages
that it produced are included as part of the user output.
* Move GitHub API module to utils/github.rb.
* Move curl method to utils/curl.rb.
* global: use long curl arguments and an array.
This makes the code more self-documenting.
* utils/curl: support reading curl's output.
* utils/github: use curl instead of open-uri.
It has far better proxy support.
* pull: set Homebrew user agent.
* gist-logs: remove trailing whitespace.
* gist-logs: use first instead of [0].
Easier to read.
* gist-logs: use curl-based GitHub.open method.
