Currently most traders have inappropiate (e.g. circular) footprints; this patch corrects them. (See also D2496.)
Before: {F1234073}
After: {F1238638}
Notice that donkey traders are centred on the human, not the donkey (@Stan).
Fundamentally there are four types of traders:
* camel: cart, pers, ptol
* donkey: brit, gaul, iber, kush
* horse-drawn cart: athen, mace, rome, sele, spart
* ox cart: maur
Because none of them has a majority, footprints have to be defined in the individual specific templates, not in the generic shared parent.
While at it, also performed the following <Identity> corrections:
* Greek specific names
* ptol icon
* spart language