Filter out repeat events for mouse buttons.

Not many mice do this, but some do, Apple Mighty Mouse in particular, and
it makes click-and-drag pretty much impossible to use.

Arguably we should filter _all_ repeat events from the kernel and handle
synthesizing them in the server.

src/evdev.c

@@ -251,6 +251,11 @@ EvdevReadInput(InputInfoPtr pInfo)
 	    break;
 
         case EV_KEY:
+	    /* don't repeat mouse buttons */
+	    if (ev.code >= BTN_MOUSE && ev.code < KEY_OK)
+		if (value == 2)
+		    break;
+
             switch (ev.code) {
 	    /* swap here, pretend we're an X-conformant device. */
             case BTN_LEFT: