Use a fence instead of semaphore to signal the acquire of the next swapchain image
Use a fence instead of semaphore to signal the acquire of the next swapchain image

Previously the acquire was using a semaphore, and the submission of the primary
command buffer to the queue was dependent on the semaphore, but this ignored the
image layout transition.  So use a fence instead.  There is no change in the
behaviour on AMD, however.

StrayLightning/wyvern