Add very initial support for Visual Studio 2015
Add very initial support for Visual Studio 2015

The new compiler is not detected automatically yet.
You have to use --with-visual-studio=2015 to enable it.

Change-Id: I0ef8cda7b2d99389b39fd7f8c2e142453ced99ed
Reviewed-on: https://gerrit.libreoffice.org/15644
Reviewed-by: David Ostrovsky <aa743a0aaec8f7d7a1f01442503957f4d7a2d634@ostrovsky.org>
Tested-by: David Ostrovsky <aa743a0aaec8f7d7a1f01442503957f4d7a2d634@ostrovsky.org>

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core