Move the initialization of BandLimitedWaves into engine.cpp

Since we now provide the wavetables as pre-generated files, there's no delay caused by their initialization
so we can move it to the startup of the software. I thought engine.cpp is the best place for this, it makes
conceptually more sense than main.cpp IMO.
This way each instrument that wants to use them in the future won't have to call the initialization function
separately, making things a bit easier.

src/core/BandLimitedWave.cpp

@@ -30,6 +30,34 @@ WaveMipMap BandLimitedWave::s_waveforms[4] = {  };
 bool BandLimitedWave::s_wavesGenerated = false;
 QString BandLimitedWave::s_wavetableDir = "";
 
+
+QDataStream& operator<< ( QDataStream &out, WaveMipMap &waveMipMap )
+{
+	for( int tbl = 0; tbl <= MAXTBL; tbl++ )
+	{
+		for( int i = 0; i < TLENS[tbl]; i++ )
+		{
+			out << waveMipMap.sampleAt( tbl, i );
+		}
+	}
+    return out;
+}
+
+QDataStream& operator>> ( QDataStream &in, WaveMipMap &waveMipMap )
+{
+	sample_t sample;
+	for( int tbl = 0; tbl <= MAXTBL; tbl++ )
+	{
+		for( int i = 0; i < TLENS[tbl]; i++ )
+		{
+			in >> sample;
+			waveMipMap.setSampleAt( tbl, i, sample );
+		}
+	}
+    return in;
+}
+
+
 void BandLimitedWave::generateWaves()
 {
 // don't generate if they already exist

src/core/engine.cpp

@@ -43,6 +43,7 @@
 #include "Plugin.h"
 #include "SongEditor.h"
 #include "song.h"
+#include "BandLimitedWave.h"
 
 
 bool engine::s_hasGUI = true;
@@ -72,6 +73,9 @@ void engine::init( const bool _has_gui )
 {
 	s_hasGUI = _has_gui;
 
+	// generate (load from file) bandlimited wavetables
+	BandLimitedWave::generateWaves();
+
 	initPluginFileHandling();
 
 	s_projectJournal = new ProjectJournal;