Merge pull request #3 from amifsud/master

Add commandds for changing coefficients and measurement of the time of the flexibility computation
small improvements and cleaning
Add a definition of a 3x3 unaligned matrix
Add rotation Matrix version instead of quaternion.

- Move implementation of rigid body kinematics to inline versions.
Add a rotation matrix mode for sensors implementation
Move to rotation matrix description of the elastic local frame dynamics
Switch to lowercase for constants.
Add some member variables and the related interfaces.
Optimize the kinematics routines.
Add a first order integrator

Improve the implementations and documentations of the second order integrators.
Reimplement the dynamics methods.
Code refactoring...

... by removing the reference to time from the indexed matrix array name and routines
Refactoring...

move all the dynamics to a dedicated motion.
Add oversampling and Runge and Kutta 4

Clean the standard outputs
Correct modification of the Kalmqn filter base
small cleaning of imu-elastic-local-frame-dynamical-system