Use buster-istanbul for build coverage.
Add more integration test cases.
Add coverage to CI run.
Modify Jenkins constructor, proxy is now part of opts. Move env var http_proxy handling from client to Jenkins constructor.
Add 'bob build' alias to simplify build targets chaining.
Fix main module, handy for using Jenkins directly as lib instead of cli and irc.
Lose setUp quotation marks.
Simplify proxy setting since bag.http.request takes care of request's proxy opt setting.