common: Move settings to common from core.

- Removes a dependency on core and input_common from common.

src/core/core.h

@@ -388,6 +388,9 @@ public:
      */
     void ExecuteProgram(std::size_t program_index);
 
+    /// Applies any changes to settings to this core instance.
+    void ApplySettings();
+
 private:
     System();