Merge lp://staging/~jderose/ubuntu/saucy/gnome-settings-daemon/tune-syndaemon2 into lp://staging/ubuntu/saucy/gnome-settings-daemon

See https://bugs.launchpad.net/ubuntu/+source/gnome-settings-daemon/+bug/1215463

On a modern laptop with a large touchpad/clickpad, your palms tend to brush the touch surface as you type. The problem is that on Ubuntu, this creates an annoying amount of cursor wiggle. Competing platforms don't have this problem, so this needs to be improved on Ubuntu.

Part of the problem is the is that `xserver-xorg-input-synaptics` driver doesn't do effective palm detection (it seems), and part of the problem is that `gnome-settings-daemon` launches `syndaemon` such that it *never* disables cursor movement.

Currently syndaemon is launched like this:

  syndaemon -i 1.0 -t -K -R

The "-t" option tells syndaemon to never block cursor movement. It will only block accidental vertical scrolling (which is darn near impossible to do on a modern system with two finger scrolling), and block accidental tap-to-click (which seems unlikely something you can do by mistake with your palms). So from a user perspective, "Disable while typing" currently does nothing.

I'm proposing that syndaemon instead be launched like this:

  syndaemon -i 0.5 -K -R

Without the "-t" option, syndaemon will block cursor movement, vertical scrolling, and tap-to-click. And the "-i 0.5" means it will block it for 500ms (half a second).

System76 has been shipping a patched `gnome-settings-daemon` (Raring) on all our products for the last two months, and we've received no support issues about it (if this caused noticeable usability issues, I'm confident we'd have heard about it).

We've also done a lot of testing and tuning on the timeout threshold, and 500ms seems like about the sweet spot. It's long enough to be decently effective for most typists, but not so long that the user will catch the trackpad still disabled when they move from typing back to "cursoring" :P

Note that this isn't a prefect solution, and you really can't do this especially well with a static timeout anyway (would be better to be dynamic based on typing speed). For slow typists, 500ms often isn't long enough. But for now, I feel it's better to find that sweet spot where it at least gives some improvement for most users, without causing any negative impact for any users.