libnm-gtk: fix library gettext usage (bgo #741215)

Libraries need to include <gi18n-lib.h>, not <gi18n.h>, so that _()
will get defined to "dgettext (GETTEXT_DOMAIN, string)" rather than
"gettext (string)" (which will use the program's default domain, which
works fine for programs in the network-manager-applet tree, but not for
external users). Likewise, we need to call bindtextdomain() so that
gettext can find the translations if the library is installed in a
different prefix from the program using it (and
bind_textdomain_codeset(), so it will know the translations are in
UTF-8 even if the locale isn't).

(based on NM commit 53f5e9afa466b0b1517cbac208ed01ab8f4b6274)

https://bugzilla.gnome.org/show_bug.cgi?id=741215
(cherry picked from commit 078b945806b56ff663d051fdd9c228e7ef68d23e)
applet: remove pos from applet_menu_item_add_complex_separator_helper()

Remove a redundant parameter that was allways set to -1 by the caller
and the related code.

(cherry picked from commit 995b6800661948c4f6760641effdee924f40c440)
applet: fix nm-applet tooltip when a VPN connection is active (bgo #737585)

Active VPN connections contain a device of a base connection, but we are
interested in the base active connection itself.

https://bugzilla.gnome.org/show_bug.cgi?id=737585
(cherry picked from commit 64d744e99e7cf55e486dd51ed083d42e9e1c9c49)
applet: make applet_find_active_connection_for_device() static

It is only used in applet.c.

(cherry picked from commit d63ad671fd20a0dfc82738eecb4e7b4e013311ee)
libnm-gtk: use Bluetooth name for disambiguation

Currently if we have two paired bluetooth devices,
nma_utils_disambiguate_device_names() will disambiguate them by their
hardware address.  This is not very helpful, so detect this case and use
the Bluetooth device name instead.

This function is used by System Settings when showing the list of
network devices.

https://bugzilla.gnome.org/show_bug.cgi?id=740553
(cherry picked from commit 74d110a9326da1644788f16a4a6e3ed1631592e8)
gconf: support reading int64 properties

Now that we've got int64 properties (route metric) let's make sure
the testcases don't fail with them.

(cherry picked from commit 1e6e4ceba6e2a022a484db25c796939845df6e08)