Extracted VS version lookup code in build script.
Extracted VS version lookup code in build script.

ddobrev/CppSharp,u255436/CppSharp,ktopouzi/CppSharp,inordertotest/CppSharp,zillemarco/CppSharp,mohtamohit/CppSharp,ddobrev/CppSharp,ktopouzi/CppSharp,zillemarco/CppSharp,mono/CppSharp,ddobrev/CppSharp,mono/CppSharp,inordertotest/CppSharp,zillemarco/CppSharp,ktopouzi/CppSharp,mohtamohit/CppSharp,mohtamohit/CppSharp,inordertotest/CppSharp,u255436/CppSharp,mono/CppSharp,mono/CppSharp,ktopouzi/CppSharp,ddobrev/CppSharp,u255436/CppSharp,zillemarco/CppSharp,mohtamohit/CppSharp,ktopouzi/CppSharp,mono/CppSharp,ddobrev/CppSharp,inordertotest/CppSharp,u255436/CppSharp,inordertotest/CppSharp,mohtamohit/CppSharp,mono/CppSharp,u255436/CppSharp,zillemarco/CppSharp