various changes from the ssc svn post-public beta 2 release.

* New Lua bindings SONGMAN:GetGroupNames() and SONGMAN:GetSongsInGroup(string)
* Add Lifts to PaneDisplay (StepMania 3.9+ added them)
* Fix an issue where course banners were able to trip off the uneven dimensions dialog
* NextSong/PrevSong now work when TwoPartSelection=true + TwoPartConfirmsOnly=true on ScreenSelectMusic. A new message ("TwoPartConfirmCanceled") was added to catch when this happens.
and there may have been some stray cleanup in here too

src/GameConstantsAndTypes.h

@@ -29,6 +29,7 @@ enum RadarCategory
 	RadarCategory_Mines,
 	RadarCategory_Hands,
 	RadarCategory_Rolls,
+	RadarCategory_Lifts,
 	RadarCategory_MinMidiNote,
 	RadarCategory_MaxMidiNote,
 	NUM_RadarCategory,	// leave this at the end
@@ -54,7 +55,7 @@ enum StepsType
 	StepsType_dance_double,
 	StepsType_dance_couple,
 	StepsType_dance_solo,
-	//StepsType_dance_three,
+	//StepsType_dance_three, // kurisu calls this "3panel"
 	StepsType_dance_routine,
 	StepsType_pump_single,
 	StepsType_pump_halfdouble,