ENH: improve tree supports

1. speedup organic tree support by using parallel for intersection of bed area
jira: STUDIO-8451
2. add extra wall for hybrid tree support's tall branches
3. disable circle fitting for tree support. This feature produces inconsistent
   circles for tree supports.
4. expose the option tree_support_branch_diameter_angle. Tree supports'
   strength can be improved by increasing this value.

Change-Id: If3688ca895df98a77f6ca538077daf8fe94e53f1
(cherry picked from commit 7697eb3dc8f87204d28e6be9adaf55dfcdadbc74)

src/libslic3r/Support/TreeSupport3D.cpp

@@ -36,6 +36,7 @@
 
 #include <tbb/parallel_for.h>
 #include <tbb/parallel_for_each.h>
+#include <tbb/spin_mutex.h>
 
 #if defined(TREE_SUPPORT_SHOW_ERRORS) && defined(_WIN32)
     #define TREE_SUPPORT_SHOW_ERRORS_WIN32
@@ -3551,7 +3552,9 @@ static void generate_support_areas(Print &print, TreeSupport* tree_support, cons
         print.set_status(69, _L("Generating support"));
         generate_support_toolpaths(print_object.support_layers(), print_object.config(), support_params, print_object.slicing_parameters(),
             raft_layers, bottom_contacts, top_contacts, intermediate_layers, interface_layers, base_interface_layers);
-
+        
+        auto t_end = std::chrono::high_resolution_clock::now();
+        BOOST_LOG_TRIVIAL(info) << "Total time of organic tree support: " << 0.001 * std::chrono::duration_cast<std::chrono::microseconds>(t_end - t_start).count() << " ms";
  #if 0
 //#ifdef SLIC3R_DEBUG
         {