Update NewtonScene.m

Fixing typo in comment in onEnter
[Pr -> Per]
Update HelloWorldScene.m

Fixing typo in comment in onEnter
[Pr -> Per]
Update CCTransition.h

Splitting out documentation for incomingDownScale and incomingSceneAnimated so that they wont get lost when the documentation files are generated.
Merge pull request #520 from richardgroves/develop-v3

Fixing a typo in comments in onEnter in two Scene files in the new project template