make these two asserts more helpful

src/ScoreKeeperNormal.cpp

@@ -360,14 +360,14 @@ void ScoreKeeperNormal::AddScoreInternal( TapNoteScore score )
 		
 	}
 
-	ASSERT( iScore >= 0 );
+	ASSERT_M( iScore >= 0, "iScore < 0 before re-rounding" );
 
 	// Undo rounding from the last tap, and re-round.
 	iScore += m_iScoreRemainder;
 	m_iScoreRemainder = (iScore % m_iRoundTo);
 	iScore = iScore - m_iScoreRemainder;
 
-	ASSERT( iScore >= 0 );
+	ASSERT_M( iScore >= 0, "iScore < 0 after re-rounding" );
 
 	// LOG->Trace( "score: %i", iScore );
 }