QwtNaturalSplineCurveFitter, QwtParametricSplineCurveFitter temorarily
added ( won't stay for long )


git-svn-id: svn://svn.code.sf.net/p/qwt/code/trunk@1833 29e17f8d-cf37-471e-a288-72cc03a76eda
bezier fitting algo fixed


git-svn-id: svn://svn.code.sf.net/p/qwt/code/trunk@1834 29e17f8d-cf37-471e-a288-72cc03a76eda
curve fitters in qwt_spline_curve_fitter again, QwtSpline removed


git-svn-id: svn://svn.code.sf.net/p/qwt/code/trunk@1835 29e17f8d-cf37-471e-a288-72cc03a76eda