Refactored angle-prefab: Building Circle-Segment (used as the angle-representation) from Script now, using Mesh-API. Now angles > 90 degrees look much better (are not stretched or compressed in an ugly way), and potentially also angles > 180 degrees could be measured.

Fixed json-payload for OnLineFacts and LineFacts + Adjustments so that SupplementaryAngles-Scroll works again + Adjusted GET on Scroll/List-endpoint in DisplayScrolls so that it tries several times, because server mostly returns a 500 on first try

Fixed bug occuring when assigning fact during hint-animation + Set default of selected scroll to OppositeLen