人口增加几率改为    房子人数*概率
Merge branch 'master' of https://github.com/LuciusYu/TownSimulator.git

Conflicts:
	TownSimulator/src/com/TownSimulator/entity/building/ApartmentHouse.java
	TownSimulator/src/com/TownSimulator/entity/building/LowCostHouse.java