This patch adds a new variable scope for CPU registers in the GDB backend:
- Unavailable registers are not shown.
- Values are shown using the raw format.
Changed CPU registers are highlighted if it is supported by the debugger:
- The Locals View class now can highlight changed variables for both backends, although currently it is only used by GDB in the CPU registers variable scope.
- The names of the changed registers use a bold font.
- Added a new capability field in the GDB backend.
