Changeref not connected

[ldeniau]

The Changeref element is not connected while all sub-patches required for its implementation are there. Twiss has a guard emitting a warning, but not Track nor Survey. We should maybe discuss the order of the sub-patches to ensure the compatibility with MAD-NG (including attributes names, to be discussed). https://github.com/MethodicalAcceleratorDesign/MAD/blob/dev/src/madl_dynmap.mad#L241 (Track, Twiss) https://github.com/MethodicalAcceleratorDesign/MAD/blob/dev/src/madl_geomap.mad#L121 (Survey)