Lambda/Role changes

[drboyer]

What's this PR?

• Explicitly sets the Version in policies in all Roles this library generates (Closes #112)
  • Switches the Lambda shortcut to use the ServiceRole shortcut, so it automatically picks up the above shortcut
• Adds a new RoleArn parameter to Lambda shortcuts, enabling users to pass an existing role instead of always creating a new one (Closes #103)
• Switches test reporting to tap-spec because I like how it shows me exactly what failed at the bottom of my test runs 😎

What's left?

I left a question in #103 about some advanced functionality @rclark originally suggested. We should probably come to a conclusion on that before merging this.

About this review

• Are my new/updated comments logical?
• Sorry for all the fixture updates - this change reordered templates which meant lots of fixture updates (and meant I made use of the UPDATE environment variable)

[drboyer]

I've updated this PR to attach a new LogPolicy to all Lambdas, per discussion. Based on that I had to re-jigger some configuration in the Stream and Queue lambdas, but hopefully the change makes sense.

I'll give this a try in a PR where I'd like to provide my own role, but in the meantime, putting this back up for review.