• added ppc64le support
• added new vk_validation mode which enables VK_VALIDATION_FEATURE_ENABLE_BEST_PRACTICES_EXT
• VK_IMAGE_USAGE_TRANSFER_SRC_BIT is now optional if the target device doesn't support it
• added vk_restart console command which rebuilds Vulkan renderer without recreating entire window - this helps with proper handling of certain errors, such as VK_ERROR_OUT_OF_DATE_KHR
• application window is now recreated from scratch only if really necessary