* Bug: In cumulus/plugins/PadsCorona.py, when a pad is at the beginning
or at the end of the side, the pad corona terminal may be outside
the corona range (not directly facing it). In that case, create a
bend to reach it.
Worse, in some case more than one (but likely no more), could be
in that case, so not only do we create a bend but also make a
shift in the bended segment so two consecutive ones are not on the
same axis, causing shorts.
If both end pads of a corner are in that case, we cannot prevent
a short, so at least, issue a warning.
* Bug: In CRL::Vhdl, the Entity::VstUseConcat was not passed correctly
along, so we did get a strange mix of conat and direct assignment.
* New: In Unicorn/cgt.py : added --vst-use-concat options to control
the VST driver behavior.