[niepce] (17 commits) ...Update requirements

[Hubert FiguiÃre <hub src gnome org>]

Summary of changes:

  7e25501... First shot at building for Gtkmm 3.0 Remove gconf and repla (*)
  b9eba69... Replace GtkTable with GtkGrid in the UI files. Get rid of . (*)
  bcb5f1e... Remove the custom theme Use Gtk::Settings to say "prefer da (*)
  67b42d9... Fix headers for newer glibmm (*)
  41e7ffc... Fix for Glibmm master: fix include (*)
  a93cd9f... Fix the thread / mutex usage by using the new API (*)
  4c73577... Fix the click on the cell to rate for Gtk3. (*)
  c058875... Revert a93cd9fb993ccdaec4db385e005c8227192037ec as it requi (*)
  57d0942... Fix the aspect of the text field
  7ae5627... Ensure the selected items are visible.
  055db84... Fix module activate / deactivate sequence
  08367f7... Populate the metadata widget once for all.
  62dd488... Token text view for keywords.
  a3587e9... Added a function in assert for breakpoints
  ff3b954... Add test for fraction
  69a0d1f... Now require Gtk
  8380846... Update requirements

(*) This commit already existed in another branch; no separate mail sent