Attempt a fix for polygons - incomplete, needs to account for position

[NathanLovato]

This is another attempt at addressing #1114 without affecting other practices. It's currently incomplete because the possibility to change the position of the turtle anytime without going through jump() needs to be taken into account as well.

[mstphayassin]

@NathanLovato I'm working on an update on this right now and it looks promising so far. Going to double and triple check that it doesn't break any other functionality throughout the app before I create a pull request though.

[NathanLovato]

Thank you very much for your contributions! Note that now there is a script included in the latest version that you can use to run an integration test that will automatically test every practice against its solution.

This will ensure that all the practices still pass with the original solution code after changes. Currently it blankets all the practices. You can always modify the script to build an array of the practices that involve the turtle instead to narrow down the test and be able to iterate a bit faster.

To run the test, open this scene in the tests/ folder and run it: integration_test_course.tscn

[NathanLovato]

Superseded by #1172