The big NULL replacement party part 1.

This is meant to be a safer alternative since
NULL can often be 0. Let's not rely on that.

And yes, I know this is a lot of files. This is
a safer thing to do in big commits vs for loops.

src/RageSoundReader_Resample_Good.cpp

@@ -667,7 +667,7 @@ int RageSoundReader_Resample_Good::Read( float *pBuf, int iFrames )
 	{
 		int iFramesNeeded = m_apResamplers[0]->NumInputsForOutputSamples(iFrames);
 		float *pTmpBuf = (float *) alloca( iFramesNeeded * sizeof(float) * iChannels );
-		ASSERT( pTmpBuf != NULL );
+		ASSERT( pTmpBuf != nullptr );
 		int iFramesIn = m_pSource->Read( pTmpBuf, iFramesNeeded );
 		if( iFramesIn < 0 )
 			return iFramesIn;