Prep work for #NOTES-less cache.

This commit should be runnable, but
I still be careful.

src/Steps.cpp

@@ -24,6 +24,11 @@
 #include "NoteDataUtil.h"
 #include "NotesLoaderSSC.h"
 #include "NotesLoaderSM.h"
+#include "NotesLoaderSMA.h"
+#include "NotesLoaderDWI.h"
+#include "NotesLoaderKSF.h"
+#include "NotesLoaderBMS.h"
+#include "NotesLoaderPMS.h"
 
 #include <algorithm>
 
@@ -78,6 +83,11 @@ unsigned Steps::GetHash() const
 	return m_iHash;
 }
 
+bool Steps::IsNoteDataEmpty() const
+{
+	return this->m_sNoteDataCompressed.empty();
+}
+
 void Steps::SetNoteData( const NoteData& noteDataNew )
 {
 	ASSERT( noteDataNew.GetNumTracks() == GAMEMAN->GetStepsTypeInfo(m_StepsType).iNumTracks );
@@ -89,7 +99,6 @@ void Steps::SetNoteData( const NoteData& noteDataNew )
 	
 	m_sNoteDataCompressed = RString();
 	m_iHash = 0;
-	m_sFilename = RString(); // We can no longer read from the file because it has changed in memory.
 }
 
 void Steps::GetNoteData( NoteData& noteDataOut ) const
@@ -250,6 +259,11 @@ void Steps::CalculateRadarValues( float fMusicLengthSeconds )
 }
 
 void Steps::Decompress() const
+{
+	const_cast<Steps *>(this)->Decompress();
+}
+
+void Steps::Decompress()
 {
 	if( m_bNoteDataIsFilled )
 		return;	// already decompressed

src/Steps.h

@@ -49,6 +49,7 @@ public:
 
 	void Compress() const;
 	void Decompress() const;
+	void Decompress();
 	/** 
 	 * @brief Determine if these steps were created by the autogenerator.
 	 * @return true if they were, false otherwise.
@@ -139,6 +140,18 @@ public:
 	void SetSMNoteData( const RString &notes_comp );
 	void GetSMNoteData( RString &notes_comp_out ) const;
 	
+	/**
+	 * @brief Retrieve the NoteData from the original source.
+	 * @return true if successful, false for failure. */
+	bool GetNoteDataFromSimfile();
+	
+	/**
+	 * @brief Determine if we are missing any note data.
+	 *
+	 * This takes advantage of the fact that we usually compress our data.
+	 * @return true if our notedata is empty, false otherwise. */
+	bool IsNoteDataEmpty() const;
+
 	void TidyUpData();
 	void CalculateRadarValues( float fMusicLengthSeconds );