Replace all code snippets in docs with references to samples

[Matthew Bolaños]

Docs should reference the code from samples to ensure that they stay up-to-date.

[David McDermott]

The docs actually walk through the code needed with a few steps. This means that some of the code in the docs doesn't match the final sample. However, the code included at the end of some of the docs should match, I think it makes sense to have those reference the code directly.