Initial commit of model file

Committing model file description for SI Epidemic model with predation.
SI process

SIS process in place, parameters result in a stable population with low
double-digit prevalence of infection.
SIS Steady State

Parameterize model to be at steady state.
More work on SILV model, creating LV based model with queues instead of pools.
Queue-based LV model

Guarenteed vs. probabilistic creation of foxes from rabbit-fox
interaction.
Added outcome

Added an outcome for a “successful” Fox-Rabbit interaction resulting in
a new Fox. This is a cumulative variable for the entire model run.
Remove success

Success counter seems to be adding computational problems. For now,
seeing if just the populations may provide interesting enough analysis.
Merge pull request #3 from elofgren/DemographicSILV

Demographic silv