Upgrade from VS2013 to VS2015
As of v2.3 the GDAL libraries are only available for C++11 and VS2015.
So we need to upgrade our codebase to VS2015 as well.
I've pulled and can confirm the solutions build fine and MapWinGIS.ocx can be registered.
SupportLibs and MapWinGIS solutions have been updated to use VS2015, and MapWinGIS now includes GDAL 2.3.0 binaries.