Add Semantics checks to Transform class

[nunoguedelha]

This change is a further step in the implementation of feature #29, with a complete support of semantics in the Transform class.

Refactored Transform class:

• Transform is now only composed of Position and Rotation class objects, without duplicated semantics elements (every Transform semantics computation relies on Position and Rotation semantics operation methods)
• Transform support of semantics covers transformation of Position, Rotation and Transform. Semantics on Twist and Wrench will come in the next days.

Note: These changes are merged with implementation of Spatial Momentum, Spatial Acceleration and Spatial Inertia (#59).

[traversaro]

LGTM, merging.

[traversaro]

Actually I just noted a possible problem: TransformSemantics class expose this two methods:

• bool setRotationSemantics(const RotationSemantics & rotation);
• bool setPositionSemantics(const PositionSemantics & position);

One can call them on a transform using transform.getSemantics().setRotationSemantics()... However if they do like this they can have a inconsisteny between the sematics stored in TransformSemantics and the one store in the Rotation object stored in Transform.

[nunoguedelha]

Both methods from TransformSemantics ...

• TransformSemantics::setRotationSemantics()
• TransformSemantics::setPositionSemantics()

... as well as those from Transform...

• Transform::setPosition()
• Transform::setRotation()

... they all call TransformSemantics::check_position2rotationConsistency() which checks the consistency of semantics.
On top of that, TransformSemantics::PositionSemantics and TransformSemantics::PositionSemantics are references to the components semantics (pos and rot). These references are initialised once and for all by the constructors at Transform instantiation.

If I missed something, any comment is most welcome.

[traversaro]

Ah yes, I forgot about the references in TransformSemantics (even if we already discussed them!)
Sorry for the noise.