Make draw_features() into a self-contained method
Make draw_features() into a self-contained method

No longer need to take a features argument: can just use the data member from the parent class
addgene/giraffe,addgene/giraffe,BjornFJohansson/giraffe,addgene/giraffe,addgene/giraffe,BjornFJohansson/giraffe,UndeadBlow/giraffe,BjornFJohansson/giraffe,UndeadBlow/giraffe,BjornFJohansson/giraffe,BjornFJohansson/giraffe