Improvements to dark theme for multi-note support
Improvements to dark theme for multi-note support

Fixes #834 and fixes #844.

- made title bar match the color of the '+ New Note' button
- icon buttons given proper :hover, :active, and :focus states
- made editor's editable area (background and color) match the rest of the dark theme

cedricium/notes,cedricium/notes,cedricium/notes,cedricium/notes,cedricium/notes