Style / structure changes from code review
- Move FieldParameter to its own file
- Extract methods in BlockSpaceEditor's flyout initialization code
- Add some documentation to procedure block method definitions
Small non-functional code review style changes:
- indentation
- ==/===s
- removal of inline comments
- inlining variable changes
Move property declarations to constructors
Refactor add parameter text event handling code
Remove description declaration from Block (currently applies to procedures only)
Feedback from review:
- Use public method for flyout height getter, setMovable for definition block
- Use function editor container presence as proxy for open status
Style and refactoring changes from code review
 - Remove some block space editor private variable references in function_editor and utils.js
 - Add names to some TODOs