Update Matlab high-level wrappers

[gabrielenava]

Hello @traversaro, I have realized that in the end we never merged the optimization of the iDynTree high level Matlab wrappers in master. Following the old PR #744 I have:

• rebased the modifications done back in time on the current master;
• fixed a bug related to a missing initialization of variables in loadReducedModel.m:
• formatted all files using the smart-indent functionality of MATLAB (ctrl+i) so that they all have the same style
• tested the code with iRonCub Matlab-based controllers and seems they work fine.

Besides the alignment of formatting style and the removal of trailing spaces, the main change is that every time the iDynTree wrappers are called, instead of creating a new object of the corresponding iDynTree class, updating it, then returning its content to matlab, they now directly update an already existing object which is created when loadReducedModel.m is called. This can save some computation time especially if a wrapper is called many times in the code. The change should not require any update of existing applications that use the wrappers.

We may try again to merge this changes in master! Let me know what you think about it.

[traversaro]

Thanks!