Better support for using symbols

[otfried]

Add possibility of choosing the symbols (it would be necessary to create a folder to insert the icons of the preview of the symbols to be implemented), rotation is often necessary in some structure symbols (I enclose an image of a technical software for structural calculation ).

https://ibb.co/G79yHDm https://ibb.co/bd1thCL

See provasimb.ipe on discussion list.

[hildogjr]

This would be super useful. I also have some "template" with symbols to start my draws.

The rotation capability is interesting but could be trick for symbols with text labels.