setup-qt introduce --detect option
setup-qt introduce --detect option

Pass --detect to autodetect qmake's from the PATH.
Passing no arguments will print the help.

Change-Id: Idf342105ee74816b0e6d07575d9aa2aab8760d3e
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@nokia.com>

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