Execute overloading

[notrab]

Fixes #235

@penberg @giovannibenussi what if we did something like this? It retains the existing behaviour, while allowing for additional argument InArgs:

client.execute({ sql: "SELECT * FROM users WHERE id = ?", args: [1] })

client.execute("SELECT * FROM users WHERE id = ?", [1])

client.execute("SELECT * FROM users")

I haven't refactored, or formatted the files. I didn't seem to find any prettier files.