implements cep21.  Agent spec's, loading, discovery.

* Cleans up Env class a lot

* added module section to master schema

* cleaned up schema - no more recipe book or catalogs (just use xml includes
  instead). Deleted all unused def/ref's that aren't needed for master schema.

* CYCLUS_MODULE_PATH->CYCLUS_PATH. and now it is a colon separated list of
  paths.

* Created AgentSpec class for dealing with agent spec parts.

* added func to manually add ref agents for dyn module Make. Useful for tests
  and other creative uses?
removed ugly extra bracing from agents' LOG calls
Merge branch 'short-log' of https://github.com/rwcarlsen/cyclus into rwcarlsen-short-log
renamed agent_impl to spec
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.
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.
Use pragma cyclus
Fix test_lotka_volterra.py and delete life event recordings.
Query the number of agents of prey prototype to determine transactions.
Working simulations for Lotka-Volterra.
fixed bug in timer and updated input file
adding some helper files -- these need to be cleaned up before merging into develop
added sim run to gen plot script
can show predatory behavior. we're still not birthing like I expect