- Update to 1.3.0:
* Add release 1.3 appdata
* Fix new appdata issues
* Specify env in travis.yml
* Stop appdata validation failing with pedantic
* Ignore debian folder
* Fix appdata id field
* Add OARS content rating
* Remove debian folder to orphan branches
* Fix variable naming convention deviations
* Fix vala-lint errors
* Change static constants to const
* Remove unused constants
* Convert to Gtk.Application
* Remove Gnonograms_ from source file names.
* Rename gnonograms.vala to Application.vala as per elementary
convention
* Fix lint found by vala-lint; consistent { get; set; } style.
* Fix README.md typo