Bugfix handling generation of person IDs

Person IDs were randomly sampled for generation on [0, maxID-1], while the
range of valid IDs is [1,maxID].
Changed mosq dist terminology, handling of RNG*

In an effort to be pedantic, the UNIFORM mosquito distribution model is now the
CONSTANT mosquito distribution model, since all houses had the same number of
mosquitoes.

Since the RNG is a global constant, it's not necessary to pass it explicitly.