vkgears: fix fences, fix angular speed, change argument parsing

Fix a bug in which vkAcquireNextImageKHR is called when back_buffer_semaphore is set or is being waited on.

Fix a bug in which the angular velocity of the gears increased during resizing the window.

Fix a small memory leak and changed argument parsing to check for parse errors.

Signed-off-by: Emimendoza emendoz@clemson.edu