Added new hermite spline interpolatin and docu. Changed tests to be based on the minified version of flot 8.3

alternative approach the special handling of fill is deactivated => line and fill in one step. Advantage: unshift can be used same ordering of hooks as before. Nicer lines because flot first works better than stack first. However not sure why the special treatment was added in the first place....

One way to solve the stacking problem we use still a new sereis for the actual line but disable stacking on new line. Drawback the process data points hook has to be after the stack hook

However, testDate still doesn't work because you get the error 'Uncaught
Error: Time mode requires the flot.time plugin. '.

../curvedLines.js
../flot/*