update bullet so it actually works

Moved the addSourceDirectory for physics/Bullet into the Engine/Source/CMakeLists.txt file that way it can actually appear where we expect it to in the solution explorer.

Engine/lib/bullet/examples/OpenGLWindow/Shaders/pointsPS.glsl

@@ -0,0 +1,10 @@
+
+#version 150
+
+in vec4 colourV;
+out vec4 fragColour;
+
+void main(void)
+{
+    fragColour = colourV;
+}