[frames] Helper functions for frames

[script/robot_wrapper] add momentum function

[script/robot_wrapper] add momentum function. add vcom and acom to separately compute the quantities

update README

Frame Jacobian Time Variation

[bindings/framejacobiantimevariation] add a function framesJacobianTimeVariation in the groove of framesJacobian that also calls compute and fk.

[algorithm/frames] add getFrameJacobianTimeVariation in the same groove as getJointJacobianTimeVariation

[algorithms][DEPRECATED] make getFrameJacobian as deprecated. getFrameJacobian<referenceframe> already exists.

[minor][robot_wrapper] frameClassicAcceleration requires numpy

Fix bug related to new version of Eigen 3.3.5

Uniformization of git history between master and devel branches

And then change name of internal ADD_UNIT_TEST to ADD_PINOCCHIO_UNIT_TEST

Merge current devel branch into master for continuous git history.
Only commits on branch devel have been kepts, devel branch being the most advanced one.

Fix bugs in exp6

Documentation and unittest for forward dynamics with damped cholesky inverse