Document "Find VC"

[sdarwin]

Among the many features of vssetup.powershell the ability to set up a developer environment is quite a useful one.

Suggestions:

• Create a wiki page in this github repository based on https://github.com/microsoft/vswhere/wiki/Find-VC "You can use vswhere.exe to find the Visual C++ compilers", and include the example script from Issue 83.

• Add a link in the README, since it's not immediately obvious to a visitor the wiki contains important content. "You can find more examples in our wiki."