First commit of 2008, Happy New Year!

Add option to compile without btClock and without profiling: comment out USE_BT_CLOCK, and #define BT_NO_PROFILE
Fixed typo/case in #include "LinearMath/btQuickProf.h", in SpuParallelSolver.cpp
Removed unnecessary files from libxml CMakeLists.txt

Demos/ConstraintDemo/ConstraintDemo.cpp

@@ -209,8 +209,7 @@ void ConstraintDemo::clientMoveAndDisplay()
 	
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
 
- 	float dt = float(m_clock.getTimeMicroseconds()) * 0.000001f;
-	m_clock.reset();
+ 	float dt = float(getDeltaTimeMicroseconds()) * 0.000001f;
 	//printf("dt = %f: ",dt);
 	
 	{