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?