New Features:
* New optional dependency: UnitTest++ (required only for running gnote tests)
* Removed dependency: boost (all of it)
* Gnote now internally uses Unicode strings for all data
Fixes:
* Fix indentation sometimes getting is lost after restart (#773630)
* Use %1 style placeholders instead of %1% in translatable strings (#774262)
* Make app menu item ordering consistent with GNOME (#772009)
* Use open-menu-symbolic icon for menu (#775320)
