[InverseDynamics] Support for Jacobians & derivatives

This change adds support for calculating Jacobians and
dot(Jacobian)*u terms, along with the required support for
the 3xN matrices in the standalone math library.
It also adds functions to compute kinematics only (position, velocity, accel).
To facilitate tests, the Cl also adds a RandomTreeCreator to create
randomized multibody trees.
Thanks to Thomas Buschmann for this contribution!

src/BulletInverseDynamics/IDConfigEigen.hpp

@@ -21,20 +21,7 @@ struct idArray {
 typedef std::vector<int>::size_type idArrayIdx;
 // default to standard malloc/free
 #include <cstdlib>
-#define idMalloc ::malloc
-
-#define idFree ::free
-// currently not aligned at all...
-#define ID_DECLARE_ALIGNED_ALLOCATOR()															 \
-	inline void* operator new(std::size_t sizeInBytes) { return idMalloc(sizeInBytes); }		   \
-	inline void operator delete(void* ptr) { idFree(ptr); }										\
-	inline void* operator new(std::size_t, void* ptr) { return ptr; }							  \
-	inline void operator delete(void*, void*) {}												   \
-	inline void* operator new[](std::size_t sizeInBytes) { return idMalloc(sizeInBytes); }		 \
-	inline void operator delete[](void* ptr) { idFree(ptr); }									  \
-	inline void* operator new[](std::size_t, void* ptr) { return ptr; }							\
-	inline void operator delete[](void*, void*) {}
-
+#define ID_DECLARE_ALIGNED_ALLOCATOR() EIGEN_MAKE_ALIGNED_OPERATOR_NEW
 // Note on interfaces:
 // Eigen::Matrix has data(), to get c-array storage
 // HOWEVER: default storage is column-major!