shell: Use GtkApplication to inhibit the screensaver

Remove TotemScrsaver copy, and use GtkApplication inhibition instead.

origin commit:
https://git.gnome.org/browse/evince/commit/?h=gnome-3-6&id=612701f

configure.ac

@@ -688,7 +688,6 @@ cut-n-paste/Makefile
 cut-n-paste/smclient/Makefile
 cut-n-paste/toolbar-editor/Makefile
 cut-n-paste/zoom-control/Makefile
-cut-n-paste/totem-screensaver/Makefile
 cut-n-paste/synctex/Makefile
 data/atril.desktop.in
 data/Makefile

cut-n-paste/Makefile.am

@@ -1,3 +1,3 @@
-SUBDIRS = zoom-control toolbar-editor totem-screensaver smclient synctex
+SUBDIRS = zoom-control toolbar-editor smclient synctex
 
 -include $(top_srcdir)/git.mk