initial check in.

config file initial definition.  playing around with ideas.
Configuration loads from some sort of json file?
Setting up tests.
improved data load

basic shim around http web traffic.

bunch of changes with defining modules;
changed config around AGAIN to be more useful.
starting to add nexus retrieval functionality, which meant
redoing a bunch of tests and adding more tests to get things in a stable place.

removed namedtuple implementation for config data, just didn't work out.
get artifacts reads a config file now but doesn't do anything else interesting.
nexus.py creates actual URLs for getting artifacts now.
clean up tmp dir and make sure it exists before downloading artifacts
Convert artifact_dict to nexus.Artifacts so we can get the URLS.
Get url for artifact in prep for downloading artifacts to temp directory
can download from nexus and write output to tmp directory now
get installers into config
include installer information, but for now only support izpack
get files from nexus and write them to the target
runs an installer via fabric
having a separate environment and data directory doesn't make sense
missed some