Add support to POST a query

[hex337]

Right now, all queries are sent via a GET, which can have limits on its length. Would be great to have the option to POST a query with the params in the body.

[BlackVegetable]

Is there a reason we wouldn't want POST to be the default here? @dkador

[dkador]

No.

[BlackVegetable]

Changing this will break a lot of tests. The actual change is very simple and works out of the box. Just... the tests are very angry.

[dkador]

Yes, we'll need to fix up the tests. :)