Graph improvements and bug fixes as follows:

 * Include panel sections in settings
 * Implement auto-add vicinity feature
 * Implement auto-remove oldest vertices if above vertex count limit
 * Include vertex outgoing degree in GraphDataProvider
 * Implement vertex color by outgoing degree
 * Auto-adjust top-count to target-count if the latter changes
 * Adjust graph vertex size and charge/distance to fit more vertices on screen