Use named parameters with Cursor and Connection objects

[austenLacy]

Closes: #232

Rather than rely on correct parameter ordering, this change switches to using named parameters to avoid out of order parameters.

This bug resulted in having to do this hack to get client certificate authentication working with Druid and Superset

hack (bad)

"engine_params": {
    "connect_args": {
      "proxies": "/path/to/my.cert"
    }
}

what it should be (good)

"engine_params": {
    "connect_args": {
      "ssl_client_cert": "/path/to/my.cert"
    }
}