Introduce Gapic-generated files for pubsub API

[swcloud]

Fixes #1463
Fixes #1549

auto-generated:
publisher_api.js
publisher_client_config.json
subscriber_api.js
subscriber_client_config.json

v1/index.js: manually written
index.js and package.json: manually modified

[stephenplusplus]

Thanks! There are just a couple of linting issues JSHint had:

$ npm run lint
> google-cloud-node@ lint /home/travis/build/GoogleCloudPlatform/google-cloud-node
> jshint scripts/ packages/ system-test/ test/ && jscs packages/ system-test/ test/

packages/pubsub/src/v1/publisher_api.js: line 500, col 2, Unnecessary semicolon.
packages/pubsub/src/v1/subscriber_api.js: line 683, col 2, Unnecessary semicolon.

[coveralls]

Changes Unknown when pulling 8a415fe on swcloud:gapic-codegen-pubsub into * on GoogleCloudPlatform:master*.

[swcloud]

@stephenplusplus Is there anyway to kickstart the Travis CI build again? The test failure on NodeJs 4 and 0.12 seemed strange to me. I run 'npm test' on my local machine which has node 4.4.7 without any problem.

[stephenplusplus]

We've been having some Travis inconsistencies lately between versions, unrelated to any changes here. It looks like the tests have been re-run and passed successfully in the meantime 👍

[coveralls]

Changes Unknown when pulling 7b6b5cd on swcloud:gapic-codegen-pubsub into * on GoogleCloudPlatform:master*.

[stephenplusplus]

Great, thanks!