readme: update link system, words, & ex. semantics
readme: update link system, words, & ex. semantics

- Links from `[title](url)` to `[title][short-name]`.

- Add links to dev.google.com docs next to the product page links (ex: [Google Cloud Pub/Sub][cloud.google.com page] ([docs][dev.google.com page])

- Use more direct wording in pubsub example to illustrate the pulling logic behind listener creation & removal

-
jonparrott/gcloud-node,jgeewax/gcloud-node,Muffasa/gcloud-node,nemo/gcloud-node,stephenplusplus/gcloud-node-bigquery-debug,anandsuresh/gcloud-node,pcostell/gcloud-node,SimpleEmotion/gcloud-node,blowmage/gcloud-node,blowmage/gcloud-node,savethefails/gcloud-node,tcrognon/google-cloud-node,jcking/google-cloud-node,pcostell/gcloud-node,callmehiphop/gcloud-node-ghpages,VikramTiwari/gcloud-node,GoogleCloudPlatform/gcloud-node,pcostell/gcloud-node,jgeewax/gcloud-node,anandsuresh/gcloud-node,stephenplusplus/gcloud-node,ofrobots/google-cloud-node,savethefails/gcloud-node,VikramTiwari/gcloud-node,chrishiestand/gcloud-node,stephenplusplus/gcloud-node,ofrobots/google-cloud-node,googleapis/google-cloud-node,phw/gcloud-node,jmptrader/gcloud-node,nemo/gcloud-node,googleapis/google-cloud-node,jmptrader/gcloud-node,GoogleCloudPlatform/gcloud-node,mziccard/gcloud-node,callmehiphop/gcloud-node,t9nf/gcloud-node,chrishiestand/gcloud-node,t9nf/gcloud-node,savethefails/gcloud-node,ofrobots/google-cloud-node,phw/gcloud-node,Muffasa/gcloud-node,SimpleEmotion/gcloud-node,jcking/google-cloud-node,t9nf/gcloud-node,Muffasa/gcloud-node,googleapis/google-cloud-node,tcrognon/google-cloud-node,GoogleCloudPlatform/gcloud-node,nemo/gcloud-node,authbox-lib/gcloud-node,callmehiphop/gcloud-node,SimpleEmotion/gcloud-node,jcking/google-cloud-node,mziccard/gcloud-node,authbox-lib/gcloud-node,VikramTiwari/gcloud-node,callmehiphop/gcloud-node-ghpages,stephenplusplus/gcloud-node-bigquery-debug,jonparrott/gcloud-node,googleapis/google-cloud-node,chrishiestand/gcloud-node,authbox-lib/gcloud-node,stephenplusplus/gcloud-node