This patch:
- Simplifies the way fields are passed to the document properties overlay
- Simplifies the way fields are filled internally in the document properties overlay
- Avoids passing a document properties reference to the secondary toolbar
This patch:
- Puts public methods at the top of the file
- Puts private methods below the public methods and marks them with an underscore
- Adds JSDoc comments to the class
- Adds setDocumentAndUrl to avoid having to handle that in `viewer.js`