Fix style errors

ref(client): add helper methods to client

fix(gitignore): ignore .DS_Store files

* since it's not being used outside of this package
* also LoadContent -> loadContent for same reason
* This addresses some style issues from #401

* Fixes some style errors in #401

Fix text alignment in dm help output.

chore(examples): add example nginx chart

On OSX, a few things we have (notably, docs) cause OS X to generate
.DS_Store caches. These should not get checked into Git.

* fixes style errors in #401

Add chart configuration

* The explanation of 'manifest' was one tab to far intended.

ref(Makefile): Check for flake8

remove unused variable

ifix(manager): test for create deployments

/cc @technosophos

This is a first pass at using the new test stub to test HTTP services.

fix(manager): add stub for context with Manager

This adds testing fixtures for the manager. It includes a stub context
that has either default or stub implementations for each object.