All extensions single revision number instead of major.minor.patch

This was decided during the August face-to-face.  Originally, the WSI
extensions did it the normal OpenGL way (single revision number), and the debug
extensions did it the new major.minor.patch way.  When I tried to convert WSI,
an objection was raised.  We decided to go with the OpenGL way.

This commit also changes vulkaninfo to report the single revision number.

This commit also changes the extension "number" assigned to the 2 debug
extensions, basd on a "registration" email that Ian Elliott sent to Jon Leech
on 21 August, 2015.  The initial set of "registered" extensions are (with their
numbers):

1.VK_EXT_KHR_swapchain
2.VK_EXT_KHR_device_swapchain
3.VK_EXT_KHR_display
4.VK_EXT_KHR_display_swapchain
5.VK_EXT_LUNARG_debug_report
6.VK_EXT_LUNARG_debug_marker
5 files changed