This patch:
- renames the elephant_stables.xml templates to elephant_stable.xml (without plural s), as well as their generic template_*.xml parent (cf. D1790/rP22322, D1860/rP22320, and D1890/rP22328)
- corrects all occurrences in simulation and map files accordingly;
- renames the stable and elephant stable audio files;
- also drops pers_ from the barrack.png and stable.png icons.