[glibmm] (7 commits) Created branch sigc3v2

[Murray Cumming <murrayc src gnome org>]

The branch 'sigc3v2' was created.

Summary of new commits:

  7833000... Use libsigc++-3.0 and C++14
  eb059a5... Try to disable -Wunused-function for the glibmm_interface_m
  9348f58... sigc++-3.0: SourceConnectionNode: Derive from sigc::notifia
  0e0689f... sigc++-3.0: SignalProxyConnectionNode: Derive from sigc::no
  f5c49ff... sigc3: .hg/.ccg files: Use sigc::slot<R(Args...)> syntax.
  f4f629d... sigc3: .h/.cc files: Use slot/signal<R(Args...)> syntax.
  5286736... sigc3: SignalProxy: Use sigc::clost<R(Args...)> syntax.