Add support for vc141 (VS2017) toolset.
Add support for vc141 (VS2017) toolset.

vswhere is shipped with all current versions of the VS Installer since 15.2 in that location and is the recommended way of detecting the presence and location of VS2017 according to the msdn blog.

gongminmin/UniversalDXSDK,gongminmin/UniversalDXSDK