Fix VSSDK files being copied into .vsix
Fix VSSDK files being copied into .vsix

cmr/VisualRust,yacoder/VisualRust,drewet/VisualRust,PistonDevelopers/VisualRust,yacoder/VisualRust,Vbif/VisualRust,Stitchous/VisualRust,Stitchous/VisualRust,xilec/VisualRust,cmr/VisualRust,vosen/VisualRust,Boddlnagg/VisualRust,PistonDevelopers/VisualRust,drewet/VisualRust,xilec/VisualRust,Boddlnagg/VisualRust,vosen/VisualRust,Vbif/VisualRust