- Overriding methods are clearly indicated with `override` keywords
- Remove redundant `virtual` keywords from destructors of subclasses
- Introduce `SPUnsupported()`, replacing most uses of
`SPNotImplemented()`, which now serves as a dynamic "TODO" marker
* Backport ngspades’s FreeType2 font renderer
* Change system fonts
* Fix SWImage::Update
* Preliminary custom TTF/OTF font support
* Fix font rendering
* Adjust design
* Update devpak
* Fix to compile on Linux
* Update .travis.yml
* Update external libraries
* Update .travis.yml
* Attempt to fix Travis CI build
* Add missing sudo to travis.yml
* Nevermind the changes, it didn't work
* Update .travis.yml
* Update .travis.yml and CMakeLists.txt