* Add intro text to components page
* Add argument to ReactPlayground, to control whether the code starts off shown. Default is false.
* Add StaticExample class, to display code snippets with syntax highlighting without the ReactPlayground editor. This needs review --- I didn't understand how the CodeMirror was used in ReactPlayground, so I copy-and-pasted.
* Add code snippets for non-react-bootstrap implementations, for comparison in the docs.
* Add draft Introduction page, explaining the project background and goals.
* Link Introduction page in docs