xorg features support

[yshui]

• [ ] keyboard: changing keyboard layout, etc.
• [x] xrdb
• [ ] clipboard
• [x] connect to a specific DISPLAY
• [x] xrandr (partially)
  • [x] get screen size info so I can recalibrate my touch screen
  • [x] handle screen change events to automatically do that every time I plug in a new monitor
  • [x] also backlight
• [x] replace xbindkeys