Full remote build given worker url

[treeder]

ie: https://github.com/iron-io/iron_worker_ruby_ng/pull/64/files#L9R46

[iced]

@treeder it's next in the list (we still miss ability to merge_gem in the build worker). proposed implementation is that merge_gem will check if it'll be executed in the build_worker (--remote switch or smth) and will than do bundle install --local on remote host and merge gems from there.

[treeder]

iron-io/top#4