[gtk] (7 commits) Non-fast-forward update to branch prop-list

[Matthias Clasen <matthiasc src gnome org>]

The branch 'prop-list' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  2969eb8... listview: Add single-click-activate
  ff00b77... Add GtkDropDown
  2ec3561... dropdown: Add a convenience constructor
  5aceb31... inspector: Use dropdowns in property editor
  bb59c01... inspector: Convert another combobox to a dropdown
  14d2544... inspector: Convert another combobox
  eb349f3... inspector: Convert another combobox

Commits added to the branch:

  ba673ed... listview: Add single-click-activate
  25ae274... Add GtkDropDown
  915f979... inspector: Use dropdowns in property editor
  78be704... inspector: Use dropdown for attribute mapping
  7189628... inspector: Use dropdown for controllers
  144d918... inspector: Use dropdown for size groups
  8c5ec8d... inspector: Use dropdowns in the visual page