- Namespaced the project.
- Modified the stylesheet to locate namespaced widgets.
- Added itchio.pri to store persistent build configurations that would
  otherwise be lost if itchio.pro were to be automatically regenerated.
- Added C++11 support.
- AppController now inherits from QApplication.
- Renamed ItchioApi to Api.
- Refactored settings: AppSettings is now known as Settings, and the
  Settings enum is now known as the Settings::Key enum class.
- The settings file is now named 'itchio.ini' (previously 'settings.scratch').
- Plugged quite a number of memory leaks and removed some unnecessary dynamic
  memory allocations (in favor of automatic allocations).
- Added the AbstractView template class to reduce repetitive code in LoginWidget,
  LibraryWidget and SettingsWidget. The downside to using this approach is that
  it breaks the uic's automatic connections feature, however this is easily fixed.
- Added a Makefile target to build the itch.io client from the command line and
  updated README.md to reflect this change.