QwtPlotPicker, QwtPlotPanner, QwtPlotZoomer adjusted


git-svn-id: svn://svn.code.sf.net/p/qwt/code/branches/qwt-6.1-multiaxes@1778 29e17f8d-cf37-471e-a288-72cc03a76eda
APIs adjusted


git-svn-id: svn://svn.code.sf.net/p/qwt/code/branches/qwt-6.1-multiaxes@1779 29e17f8d-cf37-471e-a288-72cc03a76eda