Various small updates

Hi Fayland,

I've just started using Todoist, and was very happy to write your module. I've written a basic command-line tool, which I used to import things into todoist. Would you be open to adding that to the dist? if so I'll send a pull request for that, once it's in a decent state (just a hack right now). I'll minimise the number of additional dependencies.

Anyway, here's a first bunch of changes, mainly documentation tweaks.

Cheers,
Neil