Merge pull request #33 from dhawt/master

Put layout.coffee back
Make layer and block names correspond to CSS ID of generated DOM elements.
Add validations to ensure layer names conform to valid CSS, add related tests, and include new data in generated DOM in pages#show.
DRY css name validation in a custom validator.
Merge pull request #34 from dhawt/layer_name_is_css_id

Make layer and block names correspond to CSS ID of generated DOM elements.