Vulkan/Device: Add useful accessors

Former-commit-id: b2b6378b2b9a8de2ad1c47b72f2acd6dd86a087a

include/Nazara/Vulkan/VkDevice.hpp

@@ -30,6 +30,8 @@ namespace Nz
 				inline void Destroy();
 
 				inline void GetDeviceQueue(UInt32 queueFamilyIndex, UInt32 queueIndex, VkQueue* queue);
+				inline Instance& GetInstance();
+				inline const Instance& GetInstance() const;
 				inline VkResult GetLastErrorCode() const;
 
 				inline bool WaitForIdle();
@@ -37,6 +39,8 @@ namespace Nz
 				Device& operator=(const Device&) = delete;
 				Device& operator=(Device&&) = delete;
 
+				inline operator VkDevice();
+
 				// Vulkan functions
 				#define NAZARA_VULKAN_DEVICE_FUNCTION(func) PFN_##func func