Core: Make CylindricalSurvey extend a SpatialCoordItem

This enables the reuse of UI code for map markers
Editor: CylindricalSurvey should use the missionItem as a spatialCoordItem
Rename: Rename CylindricalSurvey to StructureScanner
Rename: Fix references broken by move/rename
Merge pull request #1234 from DroidPlanner/structure_scanner_fix_1224

Structure scanner fixes