win: make buildable on VS2017

* Set default to `vs2015` since `vs2017` is not CI-green yet
* changes vcbuild.bat arg from `vc2015` to `vs2015`/`vs2017`
  `vc` as in Visual C++ is actually versions 14.0 or 14.10
  `vs` as in Visual Studio is 2015 or 2017
  Ref: http://lists.boost.org/Archives/boost/2017/03/233597.php 🤦
* keep `vc2015` for backward compatibility but "undocumented"
* tools: transplant vswhere wrapper from `msvs-com-helper`
  Ref: https://github.com/node4good/msvs-com-helper

PR-URL: https://github.com/nodejs/node/pull/11852
Reviewed-By: João Reis <reis@janeasystems.com>
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

tools/msvs/vswhere_usability_wrapper.cmd

@@ -0,0 +1,20 @@
+:: Copyright 2017 - Refael Ackermann
+:: Distributed under MIT style license
+:: See accompanying file LICENSE at https://github.com/node4good/windows-autoconf
+:: version: 1.14.0
+
+@if not defined DEBUG_HELPER @ECHO OFF
+setlocal
+set VSWHERE_REQ=-requires Microsoft.VisualStudio.Component.VC.Tools.x86.x64
+set VSWHERE_PRP=-property installationPath
+set VSWHERE_LMT=-version "[15.0,16.0)"
+SET VSWHERE_ARGS=-latest -products * %VSWHERE_REQ% %VSWHERE_PRP% %VSWHERE_LMT%
+set "VSWHERE=%ProgramFiles(x86)%\Microsoft Visual Studio\Installer"
+if not exist "%VSWHERE%" set "VSWHERE=%ProgramFiles%\Microsoft Visual Studio\Installer"
+if not exist "%VSWHERE%" exit /B 1
+set Path=%Path%;%VSWHERE%
+for /f "usebackq tokens=*" %%i in (`vswhere %VSWHERE_ARGS%`) do (
+    endlocal
+    set "VCINSTALLDIR=%%i\VC\"
+    set "VS150COMNTOOLS=%%i\Common7\Tools\"
+    exit /B 0)