add experimental vrSyncPlugin, that syncs the position/orientation of a vr controller to a gripper (through a constraint)

This is in C++ and the sync runs at the simulation speed (240 Hz), so there is less lag than in Python.
Modify the pybullet/examples/vr_kuka_setup.py at the end to do this:

plugin = p.loadPlugin("e:/develop/bullet3/bin/pybullet_vrSyncPlugin_vs2010_x64_release.dll")
controllerId = 3
p.executePluginCommand(plugin ,"bla", [controllerId,pr2_cid],[50])

examples/SharedMemory/premake4.lua

@@ -409,3 +409,6 @@ end
 include "udp"
 include "tcp"
 include "plugins/testPlugin"
+include "plugins/vrSyncPlugin"
+
+