bug: crash when upgrading house

[bahrmichael]

The mod Tycoon (0.2.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event tycoon::on_nth_tick(1800)
tycoon/city.lua:1285: attempt to index field 'tycoon_house_lights' (a nil value)
stack traceback:
tycoon/city.lua:1285: in function 'clearCell'
tycoon/city.lua:1335: in function 'upgradeHouse'
tycoon/control.lua:720: in function 'newCityGrowth'
tycoon/control.lua:968: in function <tycoon/control.lua:933>

[bahrmichael]

Fixed in 0.2.2