Depend on GTK+ 3.10

For GtkHeaderBar
Prepare 3.13.3
help: Remove old docbook help
help: Add index.page

Also adds logo images, legal.xml and Makefile.am
help: Add rules.page

Also add Makefile.am entry
help: Add puzzles.page

Also adds Makefile.am entry
help: Add start-game.page

Also adds Makefile.am entry
help: Add scores.page

Also adds Makefile.am entry
help: Add puzzles-moves.page

Also adds Makefile.am entry
help: Add moves.page

Also adds Makefile.am entry
help: Add game-introduction page

Add Makefile.am entry
Move description from index.page to game-introduction.page
help: Add keyboard shortcuts page

Also adds Makefile.am entry