Civ4lerts and growth control

[joseasoler]

Civ4lerts will throw alerts about city growing/becoming unhappy/becoming unhealthy on the next turn, even when growth control is enabled and the city won't actually grow.

[joseasoler]

Fix: Do not show city civ4lerts that will trigger after growth when growth control is enabled (resolves #262).

→ <<cset 39648102abb7>>