add random_circle function
Merge https://github.com/eah13/fall2013turtlehack into eah13-tests
Merge branch 'tests' of https://github.com/eah13/fall2013turtlehack into eah13-tests
Merge branch 'master' of https://github.com/silshack/fall2013turtlehack
Merge branch 'randomcircle' of https://github.com/eah13/fall2013turtlehack into eah13