Removed references to the SALVE root dir

The root dir of the repo is not useful when installed as a package, since it is
simply the containing dir for the package itself. Moved default_settings.ini
into the package.
Added basic support for a pip install

Minor tweaking to the layout of the main script to be workable as a setuptools
entry point as well. Allows for installation of salve as a commandline tool,
after which deployments can be managed through a simple `salve deploy ...`
Update setup.py to include default_settings.ini

This is part of the package_data field passed to the setup, as part of an
"include all .ini files" directive. This way, if more files are packaged up in
the future, they will be included as desired. Also includes argparse
dependency, fix to the license classifier, and the addition of the long
description (for presentation on pypi).
Bundled setup tooling into a Makefile

This is a little bit on the gross side, but the effect is that the Makefile can
be used to do a build without having to try to remember all of the build
tooling and commands. Overall a win. Default make target is the 'dev' build to
prevent an accidental promotion of a non-dev build into pypi when building
Update CHANGELOG to reflect updates for packaging

Some minor changes -- most notably the replacement of the SALVE_ROOT behavior
with the directory of the root manifest -- were made in order to support the
packaged version more fluidly.
Merge branch 'feature/pip-package' into dev