Backward compatibility with URDF parser (fwd_dyn param not parsed) :
Set cmake flag default value MODEL_JOINT_FWD_DYN_FROM_URDF_ON_OFF to "ALL_OFF"
Fixed setting of cmake flag MODEL_JOINT_FWD_DYN_FROM_URDF_ON_OFF.
- fixed issue: cmake flag was set after build of metapodfromurdf.cpp
Restore original URDF models format (without parameter <dynamics>-fwd_dyn).
- official urdf parser ignores this parameter but seeks for friction or dumping parameters if flag <dynamics> is present.
Merge pull request #81 from nunoguedelha/topic/R_hybrid_dynamics_algo

Topic/r hybrid dynamics algo
Fix warnings.
Optimization of overall rigid body Inertia H computing:
- implemented computing of H11 and H21 instead of full H
  (only H11 and H21 are requested for the Hybrid Dynamics
  algo. For H11 refer to Featherstone's RBDA chapter 9,
  table 9.1)
- implemented a tool identifying the root node/joint (in
  Forward Dynamics mode) supporting a given subtree
- updated unit tests and benchmarking.

Squashed commit of the following:

commit 9dd77c2765d6ea4b18acb55c9f2130b294492da4
Merge: 981040b 54165c2
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Wed Jul 2 15:38:11 2014 +0200

    v24.2.8: Merge tag 'H11_H12_H21_complete' into dbg_hybrid_dynamics_benchmark

commit 981040b06b7186095bd380b3f73478dd241ea38a
Merge: 67189ae 68faf0c
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Tue Jul 1 19:54:00 2014 +0200

    Merge tag 'H11_complete' into dbg_hybrid_dynamics_benchmark

commit 54165c2df294e118a4fc78a278d5a974ac3ae667
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Tue Jul 1 18:41:57 2014 +0200

    n24.1.8: h11, h12, h21

commit 68faf0c09fca60cf8d471dc6a42acb93c3aaae44
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Tue Jul 1 10:30:56 2014 +0200

    n24.1.7: fix compile issue due to warning->error

commit 67189ae68d7a87956f2260766c7fab3dfe33d0a7
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Tue Jul 1 14:31:18 2014 +0200

    v24.2.6: benchmark hcrba

commit 881da13ac0cfc21382c29d5dd5798e4cbc701c15
Merge: a9c84db 6d6e658
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Tue Jul 1 10:33:05 2014 +0200

    Merge tag 'H11_complete' into dbg_hybrid_dynamics_benchmark

commit 6d6e6589f1e863becc3663b892addcb1afce6a38
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Tue Jul 1 10:30:56 2014 +0200

    draft 24.1.7: fix compike issue due to warning->error

commit a9c84dbbc4cee6b036a27b9cb1d760425b4efe1a
Merge: b1f9fa1 5eaca94
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Mon Jun 30 17:46:19 2014 +0200

    Merge tag 'H11_complete' into dbg_hybrid_dynamics_benchmark

commit 5eaca943fe2fa19d5f24bd164c95d38a0813fc18
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Mon Jun 30 16:24:13 2014 +0200

    draft n24.1.6: fix H11 and H11 test

commit 38eed59100c37c0dc0710346f81b410b1af27b53
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Tue Jun 24 19:57:56 2014 +0200

    draft n24.1.5

commit cf260d68742ecdf49ec6b24d78603a7e8313e1c4
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Tue Jun 24 11:41:10 2014 +0200

    draft n24.1.4: test_hcrba complete

commit 9d3df31a676cd27bcdfbf2d1cb59663546fde26c
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Mon Jun 23 19:55:23 2014 +0200

    draft n24.1.3

commit 139567715ab9cbeab76cb998ccd32afbd77f6cab
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Fri Jun 20 19:56:49 2014 +0200

    draft 24.1.2

commit c720613e82e396a01470785e924e34fa7360118c
Author: Nuno Guedelha <nguedelh@laas.fr>
Date:   Thu Jun 19 15:55:06 2014 +0200

    draft n24.1.1

Conflicts:

        .gitignore
        benchmark/benchmark.hh
        include/metapod/algos/chda.hh
        include/metapod/algos/hcrba.hh
        tests/use_model/CMakeLists.txt
        tests/use_model/test_chda.cc
        tests/use_model/test_hcrba.cc
        tests/use_model/test_misc.cc
measuring algo steps
qcalc computed at class Robot instanciation
Inertial matrix H sparsity for Forward Dynamics computations
Inertial matrix H sparsity for Forward Dynamics computations
Fix PermutationMatrix Q element type (float to int)
Complete inertia H sparsity handling for the solver optimizing.
- implement initSparseHfromTrackNZs, for updating sparse H11 from full H11
- generate, in Robot model class constructor, the initial sparseH11 instead
  of sparseH (compute sparseH, reorder and select submatrix H11)
- in Robot model class constructor, create the sparsity LLT solver (SimplicialLLT)
  and analyse sparseH11 (reorder the nonzero elements) for optimizing later
  factorization and solving
- update sparse H11 from full H11 in CHDA step 2
- use the sparsity solver in step 3 (factorize and solve)
tests