Steps: add GetTimingData function that falls back on Song if necessary

src/Steps.cpp

@@ -520,6 +520,11 @@ void Steps::SetMeter( int meter )
 	m_iMeter = meter;
 }
 
+const TimingData *Steps::GetTimingData() const
+{
+	return m_Timing.empty() ? &m_pSong->m_SongTiming : &m_Timing;
+}
+
 bool Steps::HasSignificantTimingChanges() const
 {
 	if( m_Timing.HasStops() || m_Timing.HasDelays() || m_Timing.HasWarps() ||

src/Steps.h

@@ -157,6 +157,12 @@ public:
 	 * This is required to allow Split Timing. */
 	TimingData m_Timing;
 
+	/**
+	 * @brief Retrieves the appropriate timing data for the Steps.  Falls
+	 * back on the Song if needed. */
+	const TimingData *GetTimingData() const;
+	TimingData *GetTimingData() { return const_cast<TimingData*>( static_cast<const Steps*>( this )->GetTimingData() ); };
+
 	/**
 	 * @brief Determine if the Steps have any major timing changes during gameplay.
 	 * @return true if it does, or false otherwise. */