Update to the current preferred style
Introduction of VideoMode class & bit of refactoring of Display class; see log

* Introduce getVideoModes method call inside the Display class, using new
support VideoMode class.

- Refactoring of getDisplayColorBits method
    * Return type of const uint8
    * Provide a safe guard against segfaults when display is not yet fully
initialized.
Removal of IDisplay inheritance (for now)
Fix compile err with inline operator overloads