simplify Transformer::setup{In|Out}puts
simplify Transformer::setup{In|Out}puts

Also, the input/output properties are now removed instead
of set to undefined.

Change-Id: Ia64a8484e955525d7e186e4459f61f9b7378b0eb
Reviewed-by: Oswald Buddenhagen <6a8868beda3e139b5ac22b2534a23d3e6ba81819@digia.com>
Reviewed-by: Christian Kandeler <3aa99dcdd3f0cac61fb81c2a11771c0cc2497607@digia.com>

gatzka/qt-labs-qbs,qtproject/qt-labs-qbs,Distrotech/qbs,villytiger/qbs,gatzka/qt-labs-qbs,gatzka/qt-labs-qbs,Distrotech/qbs,qtproject/qt-labs-qbs,gatzka/qt-labs-qbs,gatzka/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,Distrotech/qbs,qt-labs/qbs,gatzka/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,Distrotech/qbs,Distrotech/qbs,qtproject/qt-labs-qbs,qt-labs/qbs,gatzka/qt-labs-qbs,villytiger/qbs,villytiger/qbs,villytiger/qbs,villytiger/qbs,qt-labs/qbs,villytiger/qbs,qt-labs/qbs,qt-labs/qbs,Distrotech/qbs,Distrotech/qbs