don't police data type connections between nodes

Nodes were previously written to be "strongly typed" in that a parameter's
"type" enforced whether it could be connected to another. All code related
to that has now been removed since not only is it hard to maintain and
likely unnecessary, it's possible the nodes will work differently later on
anyway.

app/node/block/block.h

@@ -59,8 +59,7 @@ public:
 
   NodeInput* previous_input();
 
-  NodeOutput* texture_output();
-  NodeOutput* samples_output();
+  NodeOutput* buffer_output();
   NodeOutput* block_output();
 
   static void ConnectBlocks(Block* previous, Block* next);
@@ -116,8 +115,7 @@ private:
   NodeInput* previous_input_;
   NodeOutput* block_output_;
 
-  NodeOutput* texture_output_;
-  NodeOutput* samples_output_;
+  NodeOutput* buffer_output_;
 
   rational in_point_;
   rational out_point_;