Adds more helper text to statechart_app Buildfile

Copy changes to 'app' generator over to 'statechart_app' generator. Mirrors
changes in commit 5cda3e03fae6f3c0bba5ac9fb09f79ed6aeaf675.
Merge pull request #97 from ianejames/statechart_app_buildfile

Adds more helper text to statechart_app Buildfile