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

Extras/RigidBodyGpuPipeline/dynamics/basic_demo/AMD/premake4.lua

@@ -0,0 +1,45 @@
+if os.is("Windows") then
+	
+		hasCL = findOpenCL_AMD()
+	
+		if (hasCL) then
+	
+		project "basic_bullet2_demo_AMD"
+
+		initOpenCL_AMD()
+				
+		language "C++"
+		
+		kind "ConsoleApp"
+		targetdir "../../../bin"
+
+  		includedirs {
+                "..",
+                "../../../bullet2",
+                "../../testbed",
+                "../../../rendering/Gwen",
+                "../../../opencl/basic_initialize",
+                "../../../opencl/primitives"
+                }
+		
+
+		links { "testbed",
+			"bullet2",
+			"gwen"
+		}
+		
+	
+		initOpenGL()
+		initGlut()
+
+	
+		files {
+		"../**.cpp",
+		"../**.h",
+		"../../../opencl/basic_initialize/btOpenCLUtils.cpp",
+		"../../../opencl/basic_initialize/btOpenCLUtils.h"
+		}
+
+	end
+	
+end