Exception handling is hiding the message send by standard exception

When an exception is sent by an entity it is catched by

roscontrol_sot/src/roscontrol-sot-controller.cpp

Line 940 in adc75b7

throw e;

and rethrow as it is.
It is not very informative.
A better strategy would be to indicate where this exception has been catched, print a message status, the string of the exception and rethrow.
A pull request is underway to fix this.
It appears while testing the new policy of the classical solver in https://github.com/stack-of-tasks/sot-core/blob/d9766b8f7fbfd1c2b774ba2b30c2c4e16c4be637/src/sot/sot.cpp#L472 when dealing with illogical problem formulation.

Fixed by PR#17