Patch by Kenneth Riddile: disable MSVC warnings, reenable them outside

of Eigen, and add a MSVC-friendly path in StaticAssert.

Eigen/Sparse

@@ -2,6 +2,9 @@
 #define EIGEN_SPARSE_MODULE_H
 
 #include "Core"
+
+#include "src/Core/util/DisableMSVCWarnings.h"
+
 #include <vector>
 #include <map>
 #include <cstdlib>
@@ -102,4 +105,6 @@ namespace Eigen {
 
 } // namespace Eigen
 
+#include "src/Core/util/EnableMSVCWarnings.h"
+
 #endif // EIGEN_SPARSE_MODULE_H