remove hardcoded screen name

stepmania/src/ScreenEdit.cpp

@@ -494,6 +494,8 @@ ScreenEdit::ScreenEdit( CString sName ) : Screen( sName )
 {
 	LOG->Trace( "ScreenEdit::ScreenEdit()" );
 
+	PREV_SCREEN.Load( sName, "PrevScreen" );
+	
 	ASSERT( GAMESTATE->m_pCurSong );
 	ASSERT( GAMESTATE->m_pCurSteps[0] );
 }
@@ -1506,7 +1508,7 @@ void ScreenEdit::HandleScreenMessage( const ScreenMessage SM )
 	switch( SM )
 	{
 	case SM_GoToNextScreen:
-		SCREENMAN->SetNewScreen( "ScreenEditMenu" );
+		SCREENMAN->SetNewScreen( PREV_SCREEN );
 		GAMESTATE->m_bEditing = false;
 		break;
 	case SM_BackFromMainMenu:

stepmania/src/ScreenEdit.h

@@ -16,6 +16,7 @@
 #include "NoteField.h"
 #include "song.h"
 #include "Steps.h"
+#include "ThemeMetric.h"
 
 const int NUM_ACTION_MENU_ITEMS = 23;
 const int NUM_NAMING_MENU_ITEMS = 6;
@@ -136,6 +137,8 @@ public:
 	virtual void HandleScreenMessage( const ScreenMessage SM );
 
 protected:
+	ThemeMetric<CString> PREV_SCREEN;
+	
 	void TransitionFromRecordToEdit();
 	void TransitionToEdit();
 	void PlayTicks();