applet/editor: set max-width-chars on labels to prevent wide dialogs

GTK+ 3.10 and lower capped labels with wrapping set, but without
max-width-chars set, from taking up the entire screen width.  GTK+
git master no longer does that, so some of our labels never wrap
and the dialogs look ugly.

Noticed by Michael Biebl

GTK+ 3.10 hack:
https://git.gnome.org/browse/gtk+/commit/?h=gtk-3-10&id=2436627eb4644234a9e577538ec334d224e3d2be

Backported from 7c5b4bd57db91b85a384ec16f503161bb8b35aaf
connection-editor: don't ellipsize unauthenticated CEPolkitButtons

Having CEPolkitButtons be sometimes ellipsized and sometimes not
causes the window width to change under some localizations.

After some discussion, it was decided that having to deal with an
authentication dialog does not really constitute the kind of
"additional input" that ellipses are meant to indicate, so just remove
them.

https://bugzilla.gnome.org/show_bug.cgi?id=642688
(cherry picked from commit 0fd8afcf3c2cf1675cddb4edbc73943b8234105f)
broadband: fix crash when ModemManager is not available (rh #1089765)

https://bugzilla.redhat.com/show_bug.cgi?id=1089765
(cherry picked from commit 3b7c84a9b142ec30142529a9521f985588aea255)
applet: don't block on ModemManager initialization (bgo #729334)

First, don't autostart ModemManager since the applet is only using
ModemManager for information and not for controlling modems.  Leave
that to system services (like systemd or upstart).  Requesting
autostart can block for long periods of time in some situations,
like if the process hangs during startup or isn't actually present
on the disk.

Second, make ModemManager initialization asynchronous to avoid any
other initialization blockage.  The applet only uses MM for info
about devices NM already knows about, so it's not critical to
applet startup.

https://bugzilla.gnome.org/show_bug.cgi?id=729334
(cherry picked from commit 408b88ccc38d6fa65ba7be7affb5e4bf40f4945b)
libnm-gtk: set max-width-chars on WWAN wizard labels to prevent wide dialogs

GTK+ 3.10 and lower capped labels with wrapping set, but without
max-width-chars set, from taking up the entire screen width.  GTK+
git master no longer does that, so some of our labels never wrap
and the dialogs look ugly.

GTK+ 3.10 hack:
https://git.gnome.org/browse/gtk+/commit/?h=gtk-3-10&id=2436627eb4644234a9e577538ec334d224e3d2be

(cherry picked from commit f35b9267d1309d2b69c946457a158c2379dd0e39)