Add the GPU rigid body pipeline from https://github.com/erwincoumans/experiments as a Bullet 3.x preview for Bullet 2.80

Extras/RigidBodyGpuPipeline/opencl/vector_add/stringify.py

@@ -0,0 +1,13 @@
+#!/usr/bin/env python
+import sys
+import os
+import shutil
+
+arg = sys.argv[1]
+fh = open(arg)
+	
+print 'static const char* '+sys.argv[2]+'= \\'
+for line in fh.readlines():
+	a = line.strip('\n')
+	print '"'+a+'\\n"'
+print ';'