Add `focus` argument in `Terminal.prototype.open`
Add `focus` argument in `Terminal.prototype.open`

Fix #640

cjordog/NRLWebsite,Tyriar/xterm.js,cjordog/NRLWebsite,cjordog/NRLWebsite,Tyriar/xterm.js,cjordog/NRLWebsite,sourcelair/xterm.js,sourcelair/xterm.js,xtermjs/xterm.js,akalipetis/xterm.js,akalipetis/xterm.js,akalipetis/xterm.js,akalipetis/xterm.js,sourcelair/xterm.js,xtermjs/xterm.js,Tyriar/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,xtermjs/xterm.js,sourcelair/xterm.js,Tyriar/xterm.js,Tyriar/xterm.js