main: configure script now exits properly when .config file is not found.
main: added OSX support.
frontends: added support for loading input configuration from an XML file.
chip8: cleaned up default input configuration handling.
main: resources can now have children and region mirrors are treated this way.
frontends: changed video scaling architecture improving overall performance.
main: added new clock resource type.
main: CPUs can now contain resources.
main: memory operations now rely on a bus ID (set for CPUs and controllers).
main: CPU/controller init status is now checked prior to registration.
chip8: added CPU init status check during setup.
nes: added CPU & controllers init status check during setup.
main: updated documentation wrt video frontend parameters.
main: added CPU interrupt support.