iterator: give test output for examples
iterator: give test output for examples

Implement a nonsense prime iterator (based on sieve of Eratosthenes) and
use it in the examples so that we can provide concrete output.

The cute side effect of a prime seive is that demonstrates an iterator
returning a page with fewer elements than requested (and frequently,
zero elements). The iterator uses page sizes to determine how many
numbers to consider, rather than how many to return.

Change-Id: Ia087fab92a24d6b70288a059797788b363896736
Reviewed-on: https://code-review.googlesource.com/7391
Reviewed-by: Jonathan Amsterdam <e3d3698b2ccd5955e4adf250d0785062d0f9018b@google.com>

googleapis/google-api-go-client,google/google-api-go-client,googleapis/google-api-go-client,google/google-api-go-client