docs(README): change heading for instructions on running demo app locally for clarity

Change heading from 'Running Example Application' to 'Running the Demonstration Application Locally'.
docs(CONTRIBUTING): add reminder to contributors to add their name and e-mail

Add notice for project contributors to ensure that they add their name and e-mai
l to CONTRIBUTORS.md before a PR.
Merge pull request #21 from adamjcook/docs

Modified README.md to add clarity, modified CONTRIBUTING.md to add important notice