dtvm.1: added keyboard command for pressing Mod twice
dtvm.1: added keyboard command for pressing Mod twice

tgvaughan/dvtm,lotrfan/dvtm,delphinus35/dvtm,gridsystem/dvtmx,tgvaughan/dvtm,armanbilge/dvtm,tgvaughan/dvtm,gridsystem/dvtmx,delphinus35/dvtm,lotrfan/dvtm,armanbilge/dvtm,lotrfan/dvtm