A ballot measure that would markedly curtail new homebuilding in Colorado’s fifth-largest city has stimulated a big-money effort to quash it — with developer interests amassing nearly $300,000 in contributions compared with just $4,000 from those pushing for a growth limit in Lakewood. Ballots started hitting mailboxes last week in preparation for the July 2 special election, with Question 200 the only issue to be voted on. Five issue committees have formed to defeat Question 200, which would cap annual residential growth in Lakewood at no more than 1 percent of the existing housing stock.