start by creating an application and only then a window
open config properties from application menu
application window now runs inside application
choose configuration from application headerbar
removed file menubar
added trandition, removed unused code
add and remove snapshots from treeview on singnal received
get snapshots selection from current stack child
add post snapshots on delete dialog  when the pre snapshot is selected
update glade files to 3.10. clean code
fixed duplicates in snapshot deletion
fixed case were there ane no pre snapshots in config
but there is at least one post snapshot breaking the tree constructor
cleaned imports
fixed config creation and add new config to stack
only get snapshot list when the config is selected
if only a pre snapshot is selected when creating a changes window do pre post
removed unused properties window
Merge branch 'gtk3.10'