Test random positioning.
Test position_turtle uses its parameters.
Test position_turtle randomness directly.
Test random_position uses position_turtle with no args.
Add window name argument to world, use it in asteroids and boids.
Merge pull request #10 from zeth/master

Add window name argument to world, use it in asteroids and boids.
Merge pull request #9 from OddBloke/master

Test random positioning.
Re-apply "Better clamp and wrap variable names."
Merge pull request #11 from OddBloke/master

Re-apply "Better clamp and wrap variable names."
Add tests for turn_towards.
Move tests to their own directory.
Add test for noisy function.
Merge pull request #12 from OddBloke/master

Add tests for turn_towards (and some variable renaming).