Make VS and Mingw x64 builds default to Windows 7 (_WIN32_WINNT=0x601)
Make VS and Mingw x64 builds default to Windows 7 (_WIN32_WINNT=0x601)

emoon/bgfx,aonorin/bgfx,Vertexwahn/bgfx,marco-we/bgfx,mmicko/bgfx,attilaz/bgfx,jpcy/bgfx,ming4883/bgfx,janstk/bgfx,andr3wmac/bgfx,LWJGL-CI/bgfx,mmicko/bgfx,ocornut/bgfx,elmindreda/bgfx,v3n/bgfx,sergeScherbakov/bgfx,ocornut/bgfx,BlueCrystalLabs/bgfx,BlueCrystalLabs/bgfx,cuavas/bgfx,marco-we/bgfx,ocornut/bgfx,cyndis/bgfx,kondrak/bgfx,bkaradzic/bgfx,Synxis/bgfx,attilaz/bgfx,ming4883/bgfx,septag/bgfx,LSBOSS/bgfx,mcanthony/bgfx,mcanthony/bgfx,sergeScherbakov/bgfx,marco-we/bgfx,LSBOSS/bgfx,janstk/bgfx,BlueCrystalLabs/bgfx,jpcy/bgfx,LWJGL-CI/bgfx,Vertexwahn/bgfx,MikePopoloski/bgfx,andr3wmac/bgfx,darkimage/bgfx,septag/bgfx,mmicko/bgfx,kondrak/bgfx,jdryg/bgfx,cuavas/bgfx,0-wiz-0/bgfx,emoon/bgfx,attilaz/bgfx,LWJGL-CI/bgfx,cyndis/bgfx,ktotheoz/bgfx,jpcy/bgfx,jdryg/bgfx,darkimage/bgfx,Extrawurst/bgfx,emoon/bgfx,mendsley/bgfx,aonorin/bgfx,MikePopoloski/bgfx,Synxis/bgfx,Extrawurst/bgfx,ming4883/bgfx,janstk/bgfx,kondrak/bgfx,LWJGL-CI/bgfx,darkimage/bgfx,elmindreda/bgfx,jpcy/bgfx,fluffyfreak/bgfx,fluffyfreak/bgfx,mcanthony/bgfx,bkaradzic/bgfx,Vertexwahn/bgfx,v3n/bgfx,ktotheoz/bgfx,Extrawurst/bgfx,bkaradzic/bgfx,elmindreda/bgfx,0-wiz-0/bgfx,mendsley/bgfx,ktotheoz/bgfx,cuavas/bgfx,bkaradzic/bgfx,aonorin/bgfx,sergeScherbakov/bgfx,LSBOSS/bgfx,Synxis/bgfx,mendsley/bgfx,andr3wmac/bgfx,MikePopoloski/bgfx,cyndis/bgfx,v3n/bgfx,fluffyfreak/bgfx,jdryg/bgfx,septag/bgfx,fluffyfreak/bgfx,jdryg/bgfx,0-wiz-0/bgfx