Removed <key>dmdg</key> and added a detection for Apple Monitors.

[PMheart]

This commit mainly removed dmdg since this is useless for our non-Apple monitors. And we can do nothing for Apple Monitors. So if the VID = 0x610 (Apple) and then exit.

We discussed this on Facebook yesterday. And today I updated the code. Unfortunately there is no document for the detailed action of dmdg. Nevertheless I can sure that this can do nothing for us. I didn’t know if you noticed that there are many keys inside DisplayVendorID-610, and dmdg is just one of them. Anyway, I removed it. And like above. I think DisplayVendorID-610 is mysterious. Many unknown keys existed. And we don’t know what will happen after adding these ones. So just remove them anyway. I did a detection for VID = 0x610 (Apple). Just have a look about my this commit. Anyway. Thanks for your effort on HiDPI.