Drawing Layer: Order of Elements

[danielsteinkogler]

Newly drawn shapes should always be on top; currently, rectangles, for example, are drawn below ellipses.

To achieve this the order of the shapes in the html has to be changes. Currently first all bezier lines are drawn, then all free lines aso.
This should be changed that it is iterated over all shapes and inside the loop we have to check the type of the shape and render the correct shape.

[horenso]

Should we save the order to the database? What about recently edited drawings?