Created default gui tileset.
Renamed setting tileset to entittytileset.
Added guitileset setting to VideoSetting.
main.cpp no loads gui textures via TilesetProcessor and VideoSettings.
Gui tileset path now configurable via SettingsWindow.
Added gui tilesetpath to settings.xml.
Merge pull request #56 from namelessvoid/gui-tileset

Created gui tileset and logic.

Closes #33.