Added automatic SSE3/4.1/4.2 support for MSVC.
Added automatic SSE3/4.1/4.2 support for MSVC.

pthulhu/eigen,pthulhu/eigen,cjntaylor/eigen,pthulhu/eigen,cjntaylor/eigen,pthulhu/eigen,cjntaylor/eigen,pthulhu/eigen,cjntaylor/eigen