RTC revamp (#1867)

* get this started

* implement DSi RTC commands

* set up RTC clock timer. lay down basic idea of a clock.

* make the date/time registers writable

* move RTC state to its own structure, to make it easier to deal with

* more RTC work
lay base for date/time dialog

* get the bulk of the RTC functionality going

* much simpler design for RTC stuff

* aha, that is what it is

* start working on the RTC IRQ

* implement all types of RTC IRQ

* start refining sleep mode. code still kinda sucks.

* implement keypad IRQ

* refine it some more

* shut the fuck uuuuuupppppppppppppp

src/frontend/qt_sdl/CMakeLists.txt

@@ -7,6 +7,7 @@ set(SOURCES_QT_SDL
     main_shaders.h
     CheatsDialog.cpp
     Config.cpp
+	DateTimeDialog.cpp
     EmuSettingsDialog.cpp
     PowerManagement/PowerManagementDialog.cpp
     PowerManagement/resources/battery.qrc