[Ready for Review] Chunked query responses

[pkittenis]

Changes:

• Added chunked and chunk_size keyword arguments to InfluxDBClient.query
• Added chunked response parsing of queries and chunked response test
• Added allow failure on docs for travis-ci

query doc strings now indicate that with chunked=True a list of ResultSet objects is returned with all data in the chunk.

On latest master branch trying to use chunked responses by setting params={'chunked': 'true'} would result in JSON parse failure.

[aviau]

Thanks for the good PR!

[pkittenis]

My pleasure 😄