Changed MSVC warnings from Wall to W4 to avoid 10000+ warnings from stl/windows headers.
Changed MSVC warnings from Wall to W4 to avoid 10000+ warnings from stl/windows headers.

eliben/benchmark,google/benchmark,codygray/benchmark,nickhutchinson/benchmark-cxx03,nickhutchinson/benchmark,mockingbirdnest/benchmark,nickhutchinson/benchmark,nickhutchinson/benchmark-cxx03,fuchsia-mirror/third_party-benchmark,ntx-/benchmark,mockingbirdnest/benchmark,fuchsia-mirror/third_party-benchmark,chemhack/benchmark,LepelTsmok/benchmark,LepelTsmok/benchmark,ntx-/benchmark,efcs/benchmark,fuchsia-mirror/third_party-benchmark,efcs/benchmark,disconnect3d/benchmark,disconnect3d/benchmark,eliben/benchmark,nickhutchinson/benchmark,fuchsia-mirror/third_party-benchmark,codygray/benchmark,LepelTsmok/benchmark,chemhack/benchmark,nickhutchinson/benchmark-cxx03,xlqian/benchmark,disconnect3d/benchmark,everbase/benchmark,mockingbirdnest/benchmark,nickhutchinson/benchmark-cxx03,chemhack/benchmark,disconnect3d/benchmark,codygray/benchmark,ntx-/benchmark,eliben/benchmark,google/benchmark,google/benchmark,LepelTsmok/benchmark,everbase/benchmark,efcs/benchmark,xlqian/benchmark,ntx-/benchmark,nickhutchinson/benchmark,xlqian/benchmark,everbase/benchmark,efcs/benchmark,chemhack/benchmark,eliben/benchmark,xlqian/benchmark,mockingbirdnest/benchmark,codygray/benchmark,everbase/benchmark