Add Python 3 support and optional parameter "silent" for read_gbq

[ghost]

Google's libraries support Python 3 since version 1.4.0, so we could add support for Python 3 in read_gbq method.
Also it is not always useful to see "Job not yet complete" printings, so I've added optional parameter that allows disable it.

[jorisvandenbossche]

Ca you:

• also update the tests?
• add a release note in whatsnew/v0.17.0.txt ?

[jreback]

these tests are all skipped on py3 (as I don't think the libraries are event installed), e.g. ci/requirements-3.4.txt (as compared to 2.7)

[jreback]

I don't believe ANY of the tests are actually run on travis; they are all skipped because of some import issues.

[ghost]

Than would it be merged?

[jreback]

if we have sufficient test coverage and validation

[jreback]

cc @parthea

[jreback]

issue is now #11094

pls reopen if you wish to update this issue

[parthea]

@a-rodin From version 0.17.0 onwards, you can use the verbose flag to disable printing.

To disable printing:
pd.read_gbq('SELECT * FROM test_dataset.test_table', projectid, verbose=False)

See the documentation here :
http://pandas-docs.github.io/pandas-docs-travis/io.html#io-bigquery

Fixed in #10857