This is needed for three reasons:
* To be able to arrange the icon into a folder in GNOME Software
* So that we do not allow the application to be removed
* To show the update description not in the 'OS Updates' package section
Tablets have not always an eraser (most of the generic tablets like Huion,
UC-Logic, etc... don't). We should not reject such tablets.
Commit 54849a9 (wacom: Only the stylus and eraser tools need to exist)
mentioned that we were not sure about eraser, and I think we should not
assume one either.
To do so, we simply ignore the eraser xinput node and rely on
libwacom to actually provide the eraser information.
If the stylus does not have the eraser tip, we may fall in the
LAYOUT_OTHER case. We have a picture of a generic Wacom pen with an
eraser, and the leaders linking the widget to the picture are scrambled.
To prevent that, gray out the eraser pressure slider so that we do not
break the layout.
https://bugzilla.gnome.org/show_bug.cgi?id=746117
Create the scrolled window with vertical scrolling turned off. Turn it
on when there are more than one items in the list.
Note that the immediate parent of the list is a GtkViewport, so we
need to explicitly look for the GtkScrolledWindow.
https://bugzilla.gnome.org/show_bug.cgi?id=745584
Every time we got the list of devices from the devices GtkListStore, we
were leaking the only element that wasn't a NetDevice, the proxy page.
Make sure to unref' it by hand if we're not going to add it to the list
(the elements of which will be unref'ed properly).
https://bugzilla.gnome.org/show_bug.cgi?id=746411
NetObjects and CcNetworkPanel aren't widgets, and hold references to
each other. Simplify things by having NetObject hold a pointer to
CcNetworkPanel (and the singletons NMRemoteSettings and NMClient)
instead, and clear their pointers when the original object is unref'ed.
https://bugzilla.gnome.org/show_bug.cgi?id=746411
