Clean up of hpvm-c spec

hpvm/docs/hpvm-c.md

@@ -8,9 +8,6 @@ Used before all other HPVM calls to initialize the HPVM runtime.
 ```void __hpvm__cleanup()```  
 Used at the end of HPVM program to clean up all remaining runtime-created HPVM objects.
 
-```void __hpvm__cleanup()```  
-Used at the end of HPVM program to clean up all remaining runtime-created HPVM objects.
-
 ```void llvm_hpvm_track_mem(void* ptr, size_t sz)```  
 Insert memory starting at ```ptr``` of size ```sz``` in the memory tracker of HPVM runtime.
 
@@ -30,7 +27,7 @@ Waits for completion of execution of the dataflow graph with handle ```G```.
 Push set of input data items, ```args```, (same as type included in launch) to streaming DFG with handle ```G```.
 
 ```void* __hpvm__pop(void* G)```  
-Pop and return data produced from one execution of streaming DFG with handle ```G```.
+Pop and return data produced from one execution of streaming DFG with handle ```G```. The return type is a struct containing a field for every output of DFG. 
 
 ## Internal Node API