`multipackage` Release Notes

HEAD

Add support for a manual template that allows subsystems to be specified individually in the settings file for custom usage.
Fix Sphinx documentation generation templates and add --ignore-warnings options to build_documentation.py to facilitate debugging.

Refactor code to unify all error and warning messages into a generic message structure with iter_messages(type) to select warnings or errors.
Allow templates to declare what environment variables they need based on their configured settings.
Implement multipackage doctor to show what environment variables are optional or required for a given repository.

Update ManagedFileSection.ensure_lines to support matching multiple lines with regular expressions so that you can do things like changing the pinned version of a given package in a requirements.txt file.
Update atomic_json and render_template to produce files your native line ending by default so that the files are more easily readable on each platform (since git checks them out in native line endings anyway).
Remove Sphinx warnings from pytest since they are not fixable and we can't move to Sphinx 2.0 anyway because it doesn't support Python 2.7.
Move to a template based approach for repository management where each repo has a template that installs and configures subsystems. These subsystems are then in charge of managing the repository. There is one default template named pypi_package that sets up a repository for releasing pypi packages.
Add test_by_name.py script to handle entering each component subdirectory and running the required test commands.

Update location of multipackage files to all live under a .multipackage directory. This consolidates everything into a single place and avoids cluttering up the repository. It makes multipackage more like git in that it has a folder that it manages for you and a cli tool that interacts with that folder.