Lua cutscene drawing

Format: function(cutsceneNum, sceneNum, timeSinceStart)

• cutsceneNum:
  If -1 this is the ending cutscene.
  If 0 this is the default intro cutscene.
  If >0 this is a custom cutscene.

• sceneNum:
  If 0 this is the Sonic Team Jr. presents screen (only possible during the intro cutscene.)
  If >0 this is just a regular scene.

• timeSinceStart:
  This is the time since the start of the current scene.

During the intro cutscene and ending cutscene, Lua is sent another argument: sceneEnd.
This variable tells you when the current scene is going to end.

This merge request also adds:

• The ability to disable the ending cutscene via hud.disable("endingcutscene").