Set Nu(fwd_dyn) from fwd_dyn in simple_arm and simple_humanoid models
- implement template "initNuFwdDyn" and respective unit tests:
  tests are dynamic, and fit to any fwd_dyn mapping in the URDF models
- implement cmake compile flag MODEL_JOINT_FWD_DYN_FROM_URDF_ON_OFF.
  possible string values for flag are,
  FROM_URDF => "jointFwdDyn" (in header model file) init from <dynamics>-fwd_dyn params in URDF file (this has a URDF dependency! not yet released)
  ALL_ON    => force (locally in metapod) all "jointFwdDyn" to true
  ALL_OFF   => force (locally in metapod) all "jointFwdDyn" to false

Merge commit '3f0a3739e7f79b7987f5f44bc8891880a3d30d25' into topic/hybrid_dynamics_algo_temp
Compute Permutation Matrix Q & Qt from fwd_dyn config
- refer to Featherstone Hybrid Dynamics algorithm section 9.1
- Q & Qt are static members of the model class, of type Eigen::PermutationMatrix
- template qcalc computes Q & Qt at runtime
- implemented tools/initnufwddyn.hh templates for unit testing
Merge branch 'dbg_hybrid_dynamics_nuOfFwdDyn_permutMatrixQ' into topic/hybrid_dynamics_algo
Hybrid Dynamics algorithm and unit tests:
- implemented hybrid dynamics algo (chda.hh)
- updated benchmarks
- added handling of ALL_ON and ALL_OFF joint Fwd_Dyn configurations in
  hybrid dynamics algorithm (avoid null dimension matrixes)
- added gravity parameter in rnea.hh and chda.hh
- reference files for testing chda.hh are generated automatically

Base:
Merge tag 'CHDA_base' into topic/hybrid_dynamics_algo

Conflicts:
	include/metapod/algos/chda.hh
    	robotbuilder/tpl/init.in.cc
    	robotbuilder/tpl/init.in.hh
    	tests/common.hh
    	tests/data/simple_arm/chdaTorques.ref
    	tests/use_model/test_chda.cc
    	tests/use_model/test_qcalc.cc
    	tests/use_model/test_rnea.cc
Update history, fix tabulations
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