cleans up old test files if they exist
only rm sqlite if it exists
used more clean_outs calls
Merge pull request #829 from gidden/clean

cleans up old test files if they exist
hot fixed super annoying error in ordering of state variables
Merge pull request #831 from scopatz/ord

hot fixed super annoying error in ordering of state variables
Transfer Robert's animal facility into prey and predator facilities.
Add a test file for Lotka-Volterra simulation.
Approximate input file for Lotka-Volterra.
Update behaviors of prey and predator.
Prey and predator modifications to behave correctly in isolation.
adds prototype and implementation querying by name
Clean up the code before querying the number of preys.
Fix input files and prepare tests.
Delete output dbs with clean_outs() function. Shorten the simulation.