docs: Remove VC6/7 from compatible compiler list.
docs: Remove VC6/7 from compatible compiler list.

Wohlhabend-Networks/luabind-deboostified,galek/luabind-deboostified,rpavlik/luabind,mapbox/luabind,luabind/luabind,alex85k/luabind,alex85k/luabind,Kazade/luabind-deboostified,lonski/luabind,alex85k/luabind,Oberon00/luabind,rpavlik/luabind,davidar/luabind,luabind/luabind,rpavlik/luabind,Oberon00/luabind,rpavlik/luabind,luabind/luabind,plsytj/luabind,decimad/luabind-deboostified,luabind/luabind,rpavlik/luabind,alex85k/luabind,mdave88/luabind,MrApplejuice/luabind,grafi-tt/luabind,ltjax/luabind-deboostified