Migrate Node samples to gcloud

[rakyll]

We've just released a pre-stable Datastore client with user friendly interfaces as a part of gcloud npm module. Additionally, [googleapis](the current client Node samples are using) is going to make a major release that will deprecate the current discovery model. We need to migrate to existing samples to gcloud.

[rakyll]

googleapis/google-cloud-node#6 also mentions this issue.

[anywhichway]

When using the gcloud client is the runQuery interface exposed in the dataset object returned from:

'// From Google Compute Engine:
dataset = gcloud.datastore.dataset({
projectId: 'my-project'
});'

The code I tired seems to indicate it is not ... but I might have had a bug.

[ryanseys]

As @proppy mentioned at the bottom of #50:

I think we should move the sample from this repo to the respective gcloud and google-api-nodejs-client repos.

I agree with this, I don't think that having the samples here does us any benefit because it makes things more segregated. Not sure what the approach should be (remove the samples altogether and point README at links to other samples such as gcloud-node-todos and googleapis examples folder?)

[broady]

+1, definitely should be linking to gcloud-* from the README to point people to the other libraries.

Mention that the libraries in this repo are low-level.

[eddavisson]

Cloud Datastore now has a clients landing page. The README in this project has been updated to point to that page and to make it very clear that these are low-level clients.