softgpu: Avoid unnecessary flushing for curves.

We don't need to flush all drawing between curves in softgpu, let them
queue up.

GPU/Software/TransformUnit.cpp

@@ -54,6 +54,7 @@ SoftwareDrawEngine::SoftwareDrawEngine() {
 	// All this is a LOT of memory, need to see if we can cut down somehow.  Used for splines.
 	decoded = (u8 *)AllocateMemoryPages(DECODED_VERTEX_BUFFER_SIZE, MEM_PROT_READ | MEM_PROT_WRITE);
 	decIndex = (u16 *)AllocateMemoryPages(DECODED_INDEX_BUFFER_SIZE, MEM_PROT_READ | MEM_PROT_WRITE);
+	flushOnParams_ = false;
 }
 
 SoftwareDrawEngine::~SoftwareDrawEngine() {