Remove legacy code from Admin menu init
Default Theme: Enable user-controlled zooming and scrolling of viewer

JS
* Remove: `user-scalable` and `maximum-scale` attributes in viewport meta tag
* Update: Display overlay on small screens
* Optimize: Tall viewer display

CSS
* Update: Switch CSS to production output
* Remove: Fixed viewer positioning for small screens
Merge branch 'fix_viewport_locked' into develop
Define component files by URI (instead of relative path)

* Update: File URI is stored in `uri` property (previously `path`)
* Update: Documentation reflects URI requirement
* Remove: `path` format option in `get_file()`
Update default components to use file URIs

* Update: Content Handlers
* Update: Template Tags
* Update: Themes
* Resolves #9
Merge branch 'component_file_uri' into develop