header: Update to Vulkan version 1.0.37

- header:  Updated vulkan.h
- scripts: Updated generator.py
- scripts: Updated vk.xml
- scripts: Merged recent genvk.py changes into lvl_genvk.py
- layers:  Updated json files
- loader:  Updated SOVERSION to 37
- header:  Rebuilt and updated vulkan.hpp
- layers:  Updated thread_checker for new functions
- scripts: Fix up vk_helper.py overzealous count detection

Change-Id: Ia10f5fc759166a09999f01e68bbcadb30ddf67f7