Change default to not use pthreads at startup (all calculations on main thread)

native_client_sdk/src/examples/demo/voronoi/voronoi.cc

Index: native_client_sdk/src/examples/demo/voronoi/voronoi.cc
===================================================================
--- native_client_sdk/src/examples/demo/voronoi/voronoi.cc	(revision 203001)
+++ native_client_sdk/src/examples/demo/voronoi/voronoi.cc	(working copy)
@@ -201,8 +201,8 @@
   point_count_ = kStartPointCount;
   Reset();
 
-  // By default, do single threaded rendering.
-  num_threads_ = 1;
+  // By default, render from the dispatch thread.
+  num_threads_ = 0;
   workers_ = new ThreadPool(num_threads_);
 
   // Request PPAPI input events for mouse & keyboard.