this function converts a troop string into a troop bean object.
troop bean objects are needed for use with other functions, such as city.getCarryingLoad(troopBean) or city.getTravelTime(fieldId1,fieldId2,troopBean,type)
example:
troops = "a:99.5k,w:100,wo:100,p:100,sw:100,c:90,cata:10"
troopBean = GetTroops(troops)