Tortoise: add Agents.toString for debugging
Tortoise: add patch-at
Tortoise: add hide-turtle, show-turtle
Tortoise: add patch-left-and-ahead
Tortoise: beef up TestAgents for new prims
Tortoise: add in-radius
Tortoise: Rope, Slime, Voting, Fireflies all working now
Tortoise: add n-of primitive
Tortoise: DLA Simple works now

I don't know when it started working, but it does
Merge pull request #481 from NetLogo/tortoise-more-prims-and-models

Rope, Slime, Voting, Fireflies