examples: move example.html to amd.html

Moving into the examples/ dir so that we can include other
"types" of examples, like a CommonJS example with browserify.
examples: add bower install note
examples: add a CommonJS browserify example
gitignore: ignore the `examples/build.js` file
README: add note about the `examples` dir
Merge pull request #178 from Automattic/update/add-browserify-docs-and-example

Add browserify docs and example