Also add a "rating" and "timePlayed" variable to GameData. Some cleanup
in GameData and FolderData. Added sorting functions for rating and
timesPlayed to FolderData. Testing and UI support still tbd.
Scrolling will now occur if the input is held (not just keyboards anymore!).
Initial XML gamelist support. If a file named gamelist.xml is present in the directory ES is run from, it will be parsed and the detailed GuiGameList will be used. Games are matched by absolute path, and a name, description, and image path can be read.
PugiXML is used for parsing XML files - its license can be found in src/pugiXML/pugiXML_license.txt.
SDL_image is used for loading screenshots with the detailed GuiGameList.
Almost all invalid bash characters should be escaped in ROM paths now - including !$^&*()[]<>?;'"\.
