Implement positional parameters for SQL

[proofrock]

Currently, only named params are supported:

{
    "transaction": [{
            "statement": "INSERT INTO TEST_TABLE (ID, VAL, VAL2) VALUES (:id, :val, :val2)",
            "values": { "id": 1, "val": "hello", "val2": null }
    }]
}

Implement also:

{
    "transaction": [{
            "statement": "INSERT INTO TEST_TABLE (ID, VAL, VAL2) VALUES (?, ?, ?)",
            "values": [ 1, "hello", null ]
    }]
}