Refactored BaseScreens to inherit from a new interface IHcScreen.  This allows an extra level of abstraction to be able to have bose a BaseScreen and a Child Screen.;Added new ChildScreen class for base screens to own if they potentially want to have sub scripts to pop up and then return to the previous parent upon completion.;Added a ChildScreen for the calendar in the menu as an example of this. The ChildScreen handles the loading and setting the inptu to the child screen upon loading and setting it back to parent upon finishing the screen.;Added a sample as for the calendar as a crappy placeholder. ;Cleaned up the ScreenManager and ResourceManager abit.