add basic CPU multi threading files from Bullet 2.x (still need to make it work)

btgui/MultiThreading/premake4.lua

@@ -0,0 +1,36 @@
+
+	project "App_ThreadingTest"
+		
+	kind "ConsoleApp"
+	
+--	defines {  }
+	
+	targetdir "../../bin"
+	
+	includedirs 
+	{
+		".","../../src"
+	}
+
+			
+	links { "Bullet3Common" }
+	
+	
+	files {
+		"**.cpp",
+		"**.h"
+	}
+	if os.is("Windows") then
+		--links {"winmm"}
+		--defines {"__WINDOWS_MM__", "WIN32"}
+	end
+
+	if os.is("Linux") then 
+		links {"pthread"}
+	end
+
+	if os.is("MacOSX") then
+		links {"pthread"}
+		--links{"CoreAudio.framework", "coreMIDI.framework", "Cocoa.framework"}
+		--defines {"__MACOSX_CORE__"}
+	end