Re-organized data model pages under new site structure
Clean up Getting Started page
Move other documentation under the 'documentation' directory.
Add dropdowns to navbar
Redo home page
Change page title and site title
Add Documentation index page
Standardize layouts
Fix Idiom hyperlinks
Move features to be next to, rather than inside of, idioms; rename to concepts
Sort documentation subcategories
Move descriptions of data types to data model page
Flatten idioms into one directory
Fix concept URLs
Clean up pages a bit
remove idiom layout
Add tagging to idioms
Put idioms in columns
Fix a bunch of links
Add nav links to section home pages