[GameEngine] Commit all Kester's changes made to the gameengine to restore 2.25 like physics.

[SCons] Build with Solid as default when enabling the gameengine in the build process
[SCons] Build solid and qhull from the extern directory and link statically against them

That was about it.

There are a few things that needs double checking:

* Makefiles
* Projectfiles
* All the other systems than Linux and Windows on which the build (with scons) has been successfully tested.

source/gameengine/SceneGraph/SG_Node.cpp

@@ -55,8 +55,8 @@ SG_Node::SG_Node(
 	const SG_Node & other
 ) :
 	SG_Spatial(other),
-	m_SGparent(other.m_SGparent),
-	m_children(other.m_children)
+	m_children(other.m_children),
+	m_SGparent(other.m_SGparent)
 {
 	// nothing to do
 }