use http params to specify clickhouse data format

[save-my-heart]

• fixes Query wrongly gets appended "FORMAT TabSeparatedWithNamesAndTypes" #168

It is very disgusting to rewrite sql with 'FORMAT TabSeparatedWithNamesAndTypes' and it may cause some other problems.
Instead, we can add a http params to solve it easily.
see: https://github.com/ClickHouse/ClickHouse/blob/ab9fc572d536ec9b3b7b2ac8628a3824bdeeda4c/src/Server/HTTPHandler.cpp#L734

[coveralls]

Coverage decreased (-0.04%) to 83.795% when pulling 5975561 on save-my-heart:master into f6444db on xzkostyan:master.

[villebro]

It would be great if this fix could be backported to the 0.1 version of clickhouse-sqlalchemy for projects that rely on sqlalchemy<1.4