buildFrom methods return a copy instead of a reference or void

[SamFlt]

Many classes in ViSP have a standard buildFrom method, which serves as a delayed constructor/initializer.

In many classes, this method has the signature vpObject buildFrom(Args... args). However, buildFrom modifies the calling object and there is very little sense in returning a copy.

This method should either:

• Return void: this method acts as a setter
• Return a reference: Allows for method chaining e.g. x.buildFrom(args).compute();

Currently, we can perform method chaining, but this is misleading

Some of the affected classes are:

• vpRzyxVector, vpRxyzVector, vpRzyzVector
• vpThetaUVector
• vpQuaternionVector
• vpRotationMatrix
• vpTranslationVector
• vpPoseVector
• vpVelocityTwistMatrix
• vpForceTwistMatrix

[fspindle]

We could make all the buildFrom() deprecated and introduce new functions vpObject &build(Args... args)